View source for Ex post facto law

{{Short description|Law with retroactive effect}}
{{DISPLAYTITLE:''Ex post facto'' law}}
{{Redirect|Ex Post Facto|the operating system emulator |XPostFacto|the ''Star Trek Voyager'' episode|Ex Post Facto (Star Trek: Voyager){{!}}Ex Post Facto (''Star Trek: Voyager'')}}
{{More citations needed|date=January 2021}}
An '''''ex post facto'' law'''<ref>(from {{Langx|la|ex post facto|lit=After the fact}})</ref> is a [[law]] that retrospectively changes the legal consequences or status of actions that were committed, or relationships that existed, before the enactment of the law. In [[criminal law]], it may [[Criminalization|criminalize]] actions that were legal when committed; it may aggravate a [[crime]] by bringing it into a more severe category than it was in when it was committed; it may change the [[punishment]] prescribed for a crime, as by adding new penalties or extending sentences; it may extend the [[statute of limitations]]; or it may alter the [[rules of evidence]] in order to make conviction for a crime likelier than it would have been when the deed was committed.

Conversely, a form of ''ex post facto law'' called an [[amnesty law]] may decriminalize certain acts. Alternatively, rather than redefining the relevant acts as non-criminal, it may simply prohibit prosecution; or it may enact that there is to be no punishment, but leave the underlying conviction technically unaltered. A [[pardon]] has a similar effect, except it applies in just one case instead of a class of cases. Other legal changes may alleviate possible punishments retroactively, for example by replacing the death sentence with lifelong imprisonment. Such legal changes are also known by the Latin term '''''in mitius'''''.<ref>{{Cite web |title=Qu'est-ce que la rétroactivité in mitius ? - Dissertation |url=https://www.doc-du-juriste.com/blog/conseils-juridiques/dissertation-juridique-retroactivite-in-mitius-06-03-2018.html |access-date=2024-11-17 |website=www.doc-du-juriste.com |language=fr}}</ref>

Some [[common law|common-law]] [[jurisdiction]]s do not permit retroactive criminal legislation, though new [[precedent]] generally applies to events that occurred before the judicial decision. ''Ex post facto'' laws are expressly forbidden by the [[United States Constitution]] in Article 1, Section 9, Clause 3 (with respect to federal laws) and Article 1, Section 10 (with respect to state laws). In some nations that follow the [[Westminster system]] of government, ''ex post facto'' laws may be possible, because the doctrine of [[parliamentary supremacy]] allows [[Parliament]] to pass any law it wishes, within legal constraints.{{clarify|date=July 2025}}{{citation needed|date=January 2021}} In a nation with an entrenched [[bill of rights]] or a written [[constitution]], ''ex post facto'' legislation may be prohibited or allowed, and this provision may be general or specific. For example, Article 29 of the Constitution of Albania explicitly allows retroactive effect for laws that alleviate possible punishments.

''Ex post facto'' criminalization is prohibited by [[Article 7 of the European Convention on Human Rights]], Article 15(1) of the [[International Covenant on Civil and Political Rights]],<ref>{{cite journal |last1=Ratnapala |first1=Suri |title=Ratnapala, Suri --- "Reason and Reach of the Objection to Ex Post Facto Law" [2007] UQLRS 1; (2007) 1 (1) The Indian Journal of Constitutional Law, 140-168 |journal=Classic.austlii.edu.au |date=2007 |url=http://classic.austlii.edu.au/au/journals/UQLRS/2007/1.html}}</ref> and [[Article 9 of the American Convention on Human Rights]].<ref>{{cite web |title=Article 9 Freedom from Ex Post Facto Laws {{!}} IACHR |url=https://iachr.lls.edu/violations-inter-american-convention-human-rights/article-9-freedom-ex-post-facto-laws |website=iachr.lls.edu |access-date=8 November 2020}}</ref> While American jurisdictions prohibit ''ex post facto'' laws, European countries apply the principle of '''''lex mitior''''' ("the milder law"). It provides that, if the law has changed after an offense was committed, the version of the law that applies is the one that is more advantageous for the accused. This means that ''ex post facto'' laws apply in European jurisdictions to the extent that they are the milder law.<ref>{{cite news |last1=Westen |first1=Peter |work=New Criminal Law Review: An International and Interdisciplinary Journal |title=Lex Mitior: Converse of ex post facto and window into criminal desert |date=May 2015 |pages=167–213 |doi=10.1525/nclr.2015.18.2.167}}</ref>

==''Ex post facto'' laws by country==

===Australia===
[[Australia]] has no strong constitutional prohibition on ''ex post facto'' laws, although narrowly retrospective laws might violate the constitutional [[separation of powers]] principle. Australian courts normally interpret statutes with a strong presumption that they do not apply retrospectively.

Retrospective laws designed to prosecute what was perceived to have been a blatantly unethical means of [[tax avoidance]] were passed in the early 1980s by the [[Fraser Government|Fraser government]] (see [[Bottom of the harbour tax avoidance]]). Similarly, legislation [[criminalization|criminalising]] certain war crimes retrospectively has been held to be constitutional (see ''[[Polyukhovich v Commonwealth]]'').

Australia participated in drafting the [[Universal Declaration of Human Rights]] and was an original signatory in 1948.<ref>{{cite web|title=Australia and the Universal Declaration on Human Rights|url=https://humanrights.gov.au/our-work/publications/australia-and-universal-declaration-human-rights|url-status=live|archive-url=https://web.archive.org/web/20201112022053/https://humanrights.gov.au/our-work/publications/australia-and-universal-declaration-human-rights|archive-date=12 November 2020|access-date=18 November 2020|website=[[Australian Human Rights Commission]]|language=en|quote=Australia was also one of eight nations involved in drafting the Universal Declaration.}}</ref><ref>{{cite web|title=Our commitment to human rights|url=https://www.dfat.gov.au/international-relations/themes/human-rights/Pages/human-rights|url-status=live|archive-url=https://web.archive.org/web/20201119005656/https://www.dfat.gov.au/international-relations/themes/human-rights/Pages/human-rights|archive-date=19 November 2020|access-date=19 November 2020|website=[[Department of Foreign Affairs and Trade (Australia)|Australian Government Department of Foreign Affairs and Trade]]|language=en|quote=Australia's commitment to human rights is enduring: we were an original signatory to the Universal Declaration of Human Rights in 1948.}}</ref> The Declaration includes a prohibition on retrospectively holding anyone guilty of a [[Crime|penal offence]] that was not an offence at the time it was committed.<ref>{{cite web|title=Universal Declaration of Human Rights at 70: 30 Articles on 30 Articles - Article 11|url=https://www.ohchr.org/EN/NewsEvents/Pages/DisplayNews.aspx?NewsID=23903|url-status=live|archive-url=https://archive.today/20201119004524/https://www.ohchr.org/EN/NewsEvents/Pages/DisplayNews.aspx?NewsID=23903|archive-date=19 November 2020|access-date=18 November 2020|website=[[Office of the United Nations High Commissioner for Human Rights]]|language=en-US|quote=The second paragraph of Article 11 is a ban on retroactive laws...Paragraph 2 says: "No one shall be held guilty of any penal offence on account of any act or omission which did not constitute a penal offence, under national or international law, at the time when it was committed."}}</ref> The [[Australian Human Rights Commission]] states the Declaration is an "expression of the fundamental values which are shared by all members of the international community" but "does not directly create legal obligations for countries."<ref>{{cite web|title=What is the Universal Declaration of Human Rights?|url=https://humanrights.gov.au/our-work/what-universal-declaration-human-rights|url-status=live|archive-url=https://web.archive.org/web/20201119013424/https://humanrights.gov.au/our-work/what-universal-declaration-human-rights|archive-date=19 November 2020|access-date=19 November 2020|website=[[Australian Human Rights Commission]]|language=en|quote=The Universal Declaration is not a treaty, so it does not directly create legal obligations for countries...it is an expression of the fundamental values which are shared by all members of the international community.}}</ref>

Australia is a party to the [[International Covenant on Civil and Political Rights]].<ref>{{cite web|title=International human rights system|url=https://www.ag.gov.au/rights-and-protections/human-rights-and-anti-discrimination/international-human-rights-system|url-status=live|archive-url=https://web.archive.org/web/20201119021740/https://www.ag.gov.au/rights-and-protections/human-rights-and-anti-discrimination/international-human-rights-system|archive-date=19 November 2020|access-date=19 November 2020|website=[[Attorney-General of Australia|Australian Government Attorney-General's Department]]|language=en|quote=Australia is a party to...the International Covenant on Civil and Political Rights (ICCPR).}}</ref> The implementation of retrospective criminal laws is expressly prohibited by the Covenant.<ref>{{cite web|title=Retrospective Laws|url=http://www.haveyougotthatright.com/retrospective-laws|url-status=live|archive-url=https://archive.today/20201119022350/http://www.haveyougotthatright.com/retrospective-laws|archive-date=19 November 2020|access-date=19 November 2020|website=Have You Got That Right?|language=en-US|quote=Article 15(1) of the International Covenant on Civil and Political Rights expressly prohibits the implementation of retrospective criminal laws.}}</ref> Australia is also a party to the [[First Optional Protocol to the International Covenant on Civil and Political Rights|Optional Protocol to the International Covenant on Civil and Political Rights]].<ref>{{cite web|title=International human rights system|url=https://www.ag.gov.au/rights-and-protections/human-rights-and-anti-discrimination/international-human-rights-system|url-status=live|archive-url=https://web.archive.org/web/20201119021740/https://www.ag.gov.au/rights-and-protections/human-rights-and-anti-discrimination/international-human-rights-system|archive-date=19 November 2020|access-date=19 November 2020|website=[[Attorney-General of Australia|Australian Government Attorney-General's Department]]|language=en|quote=Australia is also a party to...the Optional Protocol to the International Covenant on Civil and Political Rights.}}</ref> The Protocol enables individuals subject to the [[jurisdiction]] of a [[State (polity)|state party]] to file [[complaint]]s with the [[United Nations Human Rights Committee]] for that state party's non-compliance with the International Covenant on Civil and Political Rights.<ref>{{cite web|title=Optional Protocol to the International Covenant on Civil and Political Rights|url=https://www.equalrightstrust.org/content/optional-protocol-international-covenant-civil-and-political-rights|url-status=live|archive-url=https://archive.today/20201119024730/https://www.equalrightstrust.org/content/optional-protocol-international-covenant-civil-and-political-rights|archive-date=19 November 2020|access-date=19 November 2020|website=Equal Rights Trust|date=27 March 2009|language=en|quote=The Optional Protocol sets up a mechanism by which individuals can file complaints with the Human Rights Committee against states (which have ratified the optional protocol) for non-compliance with the provisions of the International Covenant on Civil and Political Rights (ICCPR). Notably, the mechanism is available to all "individuals subject to the jurisdiction" of the State party rather than only citizens.}}</ref>

===Brazil===
According to the 5th Article, section XXXVI<ref name=casa>[http://www.planalto.gov.br/ccivil_03/Constituicao/Constituicao.htm#art5xxxvi ide Emenda Constitucional nº 107, de 2020] Casa Civil (in Portuguese)</ref> of the [[Constitution of Brazil|Brazilian Constitution]], laws cannot have ''ex post facto'' effects that affect acquired rights, accomplished juridical acts and ''res judicata''.

The same article in section XL<ref name=casa/> prohibits ''ex post facto'' [[criminal law]]s. Like France, there is an exception when retroactive criminal laws benefit the accused person.

===Canada===
In [[Canada]], ''ex post facto'' criminal laws are constitutionally prohibited by [[Section 11 of the Canadian Charter of Rights and Freedoms|section 11(g)]] of the [[Charter of Rights and Freedoms]].  Also, under section 11(i) of the Charter, if the punishment for a crime has varied between the time the crime was committed and the time of sentencing following a conviction, the convicted person is entitled to the lesser punishment. Due to [[Section 1 of the Canadian Charter of Rights and Freedoms|section 1]] and [[Section 33 of the Canadian Charter of Rights and Freedoms|section 33]] of the [[Charter of Rights and Freedoms]] these rights are not absolute, and may be overridden.

The Canada [[sex offender registry]], which went into effect on December 15, 2004, is somewhat retroactive. When the registry was created, all offenders who were on the [[Ontario]] sex offender registry, which was created in 2001, were required to register on the national registry. In addition, sex offenders in all provinces who were serving a sentence (whether imprisoned or on probation or parole) on December 15, 2004, were required to register, regardless of when their offense and conviction occurred. However, the registry was not retroactive to anybody who had completed their sentence by late 2004 and was not on the Ontario registry.<ref name="macleans.ca">{{cite web |url=https://www.macleans.ca/news/canada/a-national-embarrassment/ |title=There's a problem with Canada's sex offender registry - Macleans.ca |website=macleans.ca |date=9 January 2008 }}</ref> Canadian courts have never ruled on the somewhat retroactive nature of the sex offender registry, since this seems to have never been challenged.

Sex offender registration was not mandatory for sex offenders until 2011, and had to be ordered by a judge.<ref>{{cite web|url=https://doubleaspect.blog/tag/sex-offender-registration/|title=sex offender registration|first=Leonid|last=Sirota|website=Double Aspect|date=30 October 2016 }}</ref><ref name="macleans.ca"/><ref>{{cite web|url=http://www.parl.ca/DocumentViewer/en/40-3/bill/S-2/royal-assent/page-ToC|title=Government Bill (Senate) S-2 (40-3) - Royal Assent - Protecting Victims From Sex Offenders Act - Parliament of Canada|website=parl.ca}}</ref> Sex offender registration was seemingly mandatory for people convicted before December 15, 2004, who were serving a sentence on that date, but was only optional for sex offenders convicted between December 15, 2004, and January 1, 2011.

Because section 11 of the Charter is among the sections that can be overridden under [[Section 33 of the Canadian Charter of Rights and Freedoms|section 33]] (the notwithstanding clause), Parliament could in theory enact ''ex post facto'' laws by invoking section 33. However, the federal Parliament, which has exclusive jurisdiction over criminal law, has never attempted to enact an ''ex post facto'' law (or any other law) using section 33.

The Charter prohibition applies only to criminal law. Changes to [[Civil law (common law)|civil law]] in Canada can be, and occasionally are, enacted ''ex post facto''. In one example, convicted murderer [[Colin Thatcher]] was ordered to forfeit proceeds from a book he had published (after being paroled from prison) under a [[Saskatchewan]] law. Although the law was passed long after Thatcher's murder conviction, the courts have ruled that such laws prescribe only [[civil penalty|civil penalties]] (as opposed to additional criminal penalties) and are thus not subject to Charter restrictions.

===Croatia===
Article 90 of the [[Constitution of Croatia]] states that "only individual provisions of a law may have a retroactive effect for exceptionally justified reasons". According to Croatian legal scholar {{ill|Branko Smerdel|hr}}, this means that "a law cannot be applied retroactively as a whole, and regulations enacted pursuant to statutory authority can never be applied retroactively".<ref>{{cite book|url=https://www.pravo.unizg.hr/_download/repository/Constitutional_law_of_28_EU_states_-_Croatia.pdf|title=Constitutional Law of 28 EU States|chapter=Croatia|last=Smerdel|first=Branko|page=206|access-date=25 May 2019|archive-date=7 May 2018|archive-url=https://web.archive.org/web/20180507144816/https://www.pravo.unizg.hr/_download/repository/Constitutional_law_of_28_EU_states_-_Croatia.pdf|url-status=dead}}</ref>

===Denmark===
{{main|Danish collaborator trials}}
Following the [[liberation of Denmark]] from [[Denmark in World War II|Nazi occupation]] in 1945, the [[Folketing]], heavily influenced by the [[Frihedsrådet|Frihedsråd]], passed a [[special law]] (Lov Nr. 259 af 1. Juni 1945 om Tillæg til Borgerlig Straffelov angaaende Forræderi og anden landsskadelig Virksomhed, colloquially ''landsforræderloven'' (the traitor law) or ''strafferetstillægget'' (the penal code addendum)), temporarily reintroducing the [[death penalty]] (previously abolished in 1930) for acts of treason committed during German occupation. Passed on 1 June 1945, the law applied to actions performed subsequent to 9 April 1940, unless those actions were done under orders from the government prior to 29 August 1943. With this authorization, 103 death sentences were issued, of which 46 were carried out.<ref>{{cite web|url=https://danmarkshistorien.dk/leksikon-og-kilder/vis/materiale/retsopgoerets-love-straffelovstillaegget-1945-til-1946/|title=Retsopgørets love - straffelovstillægget 1945 til 1946|access-date=16 August 2021|date=25 August 2011}}</ref>

===Finland===
Generally, the Finnish legal system does not permit ''ex post facto'' laws, especially those that would expand criminal responsibility. They are not expressly forbidden; instead, the ban is derived from more general legal principles and basic rights. In civil matters, such as taxation, ''ex post facto'' laws may be made in some circumstances.

Historically there have been three exceptional instances when ''ex post facto'' criminal laws have been used in Finland.

# Following the [[Finnish Civil War]] of 1918, the [[Parliament of Finland]] passed a law setting up tribunals to try suspected rebels. These tribunals issued death sentences in many cases, although very few of those accused could have committed a crime that carried the [[Capital punishment in Finland|death penalty]] under Finnish law in force during the war. Several hundred people were executed under what was arguably an ''ex post facto'' legal arrangement. During the war, and before the tribunals were set up, thousands of people had been executed without trial by both sides. However, once this phase of the civil war ended, amnesty laws were passed. Thus, the legality of the actions of the government or the participants of either side of the war cannot be legally contested anymore.
# After [[World War II]], Finland was under pressure to convict political leaders whom the Allied powers considered responsible for Finnish involvement in the war. An ''ex post facto'' law was passed in the autumn of 1945 to permit [[War-responsibility trials in Finland|prosecution for war responsibility]], and eventually eight politicians were convicted. In another post-war case, the [[Weapons Cache Case|weapons cache case]], an ''ex post facto'' law was passed in 1947 so that military personnel could be prosecuted for unofficially preparing for guerrilla resistance in case of Soviet occupation.
# During World War II, desertion, draft dodging and conscientious objection were punishable by death or jail. Amnesty laws were passed after World War II to free deserters and draft dodgers from imprisonment and further prosecution and allow them to return home without further legal consequences.

===France===
In [[France]], so-called "''lois rétroactives''" (retroactive laws) are technically prohibited by Article 2 of the [[Code Civil]], which states that: "Legislation provides only for the future; it has no retrospective operation".<ref>{{cite web|url=http://www.legifrance.gouv.fr/content/download/1950/13681/version/3/file/Code_22.pdf|title=Link to Civil Code}}</ref> In practice, however, since the Code Civil does not have the status of constitutional legislation and can therefore be overruled by subsequent laws, the {{lang|fr|[[Conseil Constitutionnel]]|italic=no}} has determined that retroactive laws can be passed within certain limits – such as in the case of financial or tax legislation –, particularly where it is considered to be in the "general interest"; this has been demonstrated by a series of decisions handed down by the Conseil Constitutionnel concerning retroactive tax laws.<ref>{{cite web |url=http://www.conseil-constitutionnel.fr/conseil-constitutionnel/francais/a-la-une/janvier-2013-la-retroactivite-fiscale-dans-la-jurisprudence-du-conseil-constitutionnel.135573.html |title=Janvier 2013: La rétroactivité fiscale dans la jurisprudence du Conseil constitutionnel |language=fr |date=January 2013}}</ref>

However, in criminal law, ''ex post facto'' sanctions are effectively forbidden as per Article 112-1 of the [[French Penal Code]], except in cases wherein the retroactive application benefits the accused person (called retroactivity ''in mitius'').<ref name = Soyer>{{cite book |last=Soyer |first=Jean-Claude |title=Droit pénal et procédure pénale |publisher=L.G.D.G. |series=Lextenso Editions |edition=21 |date=2012 |location=Paris |pages=75–78 |language=fr}}</ref> They are also considered unconstitutional, since the principle of non-retroactivity is laid down in Article 8 of the [[Declaration of the Rights of Man and of the Citizen]], which has constitutional status under French law.<ref name="Terré">{{cite book |last=Terré |first=François |title=Introduction générale au droit |publisher=Dalloz |series=Précis |edition=8 |date=2001 |location=Paris |pages=204–5 |language=fr}}</ref> The ''[[épuration légale]]'' trials held after the 1944 [[liberation of France]] introduced the status of ''[[indignité nationale]]'' for [[Collaboration with Nazi Germany and Fascist Italy|Nazi collaborators]] as a way to avoid ''ex post facto'' law.

===Germany===
Article 103 of the [[Basic Law for the Federal Republic of Germany|German basic law]] requires that an act may be punished only if it has already been punishable by law at the time it was committed (specifically: by ''written'' law, [[Germany]] following civil law).

[[Robert A. Taft]], at the time a U.S. Senator from Ohio, asserted that the [[Nuremberg Trials]] following [[World War II]] were based on ''ex post facto'' law because the Allies did not negotiate the [[Nuremberg Charter]], which defined crimes against humanity and created the International Military Tribunal, until well after the acts charged. Others, including the International Military Tribunal, argued that the London Charter merely restated and provided jurisdiction to prosecute offenses that were already made unlawful by the [[Kellogg–Briand Pact]], the [[Covenant of the League of Nations]], and the various [[Hague Conventions (1899 and 1907)|Hague Conventions]].{{Citation needed|date=February 2009}}

[[William O. Douglas]] complained that the Allies were guilty of "substituting power for principle" at Nuremberg Trials because the actions of the defendants were lawful in the 1930s Germany.  He contended that the Nuremberg Trials were implementing laws after the fact (that is, ex post facto) "to suit the clamor of the time."  American Chief Justice [[Harlan Stone]], likewise, called the Nuremberg Trials a "fraud" because of the ex post facto laws.<ref>{{cite web |last1=Linder |first1=Douglas |title=The Nuremberg Trials: An Account |url=https://famous-trials.com/nuremberg/1901-home |website=Famous Trials}}</ref>

The problem of ''ex post facto'' law was also relevant in the 1990s after [[German reunification]] as there was a discussion about the trials against [[East Germany|East German]] [[Border Troops of the German Democratic Republic|border troops]] who killed fugitives on the [[Inner German border|Inner-German border]] ([[Schießbefehl#After reunification|''Mauerschützen-Prozesse'']] – ''Wall-shooters'/ -guards' trials''). German courts in these cases recurred to the [[Radbruch formula]].<ref>Benjamin Lahusen [http://www.zeit.de/2009/46/A-Radbruch/komplettansicht "Aus Juristen Demokraten machen"]</ref>

===Hungary===
In 2010, the [[National Assembly (Hungary)|Hungarian National Assembly]] established a 98% punitive tax on any income over two million forints received either as a retirement package or as severance pay in the previous five years in the government sector.<ref>{{cite web|url=http://www.realdeal.hu/20101109/controversial-98-tax-on-govt-severance-pay-made-retroactive-to-2005|archive-url=https://web.archive.org/web/20101111025059/http://www.realdeal.hu/20101109/controversial-98-tax-on-govt-severance-pay-made-retroactive-to-2005|url-status=dead|title=Webtar.hu|archive-date=November 11, 2010|website=realdeal.hu}}</ref>

===India===
In India, without using the expression "''ex post facto law''", the underlying principle has been adopted in the article 20(1) of the [[Constitution of India|Indian Constitution]] in the following words:
{{blockquote|No person shall be convicted of any offence except for violation of a law in force at the time of the commission of the act charged as an offence, nor be subjected to a penalty greater than that which have been inflicted under the law in force at the time of commission of the offence.}}

Further, what article 20(1) prohibits is conviction and sentence under an ''ex post facto'' law for acts done prior thereto, but not the enactment or validity of such a law. There is, thus, a difference between the Indian and the American positions on this point; whereas in the United States, an ''ex post facto'' law is in itself invalid, it is not so in India. The courts may also interpret a law in such a manner that any objection against it of retrospective operation may be removed.<ref>{{cite web|url=http://www.legalserviceindia.com/article/l60-Protection-against-ex-post-facto-laws.html|title=Protection against ex-post-facto laws|website=legalserviceindia.com}}</ref>

An example for retrospective law in India is the [[Karnataka Scheduled Castes and Scheduled Tribes (Prohibition of Transfer of Certain Lands) Act, 1978]]<ref>{{cite web|url=http://www.karunadu.gov.in/karigr/actsrules/otheracts/scst.htm|title=Department of Stamps and Registration, Government of Karnataka|access-date=2014-03-26|archive-url=https://web.archive.org/web/20140326062205/http://www.karunadu.gov.in/karigr/actsrules/otheracts/scst.htm|archive-date=2014-03-26|url-status=dead}}</ref> in the state of [[Karnataka]].

===Indonesia===
The [[Constitution of Indonesia|Indonesian Constitution]] prohibits trying citizens under retroactive laws in any circumstance. This was tested in 2004 when the conviction of [[Masykur Abdul Kadir]], one of the [[2002 Bali terrorist bombing|Bali bombers]], under retroactive [[Anti-terrorism legislation|anti-terrorist legislation]] was quashed.<ref>Indonesian Constitutional Court Decision No 013/PUU-I/2003 (Masykur Abdul Kadir Case)</ref>

===Iran===
''Ex post facto'' laws, in all contexts, are prohibited by Article 169 (Chapter 11) of the [[Constitution of the Islamic Republic of Iran|Iranian Constitution]].

===Ireland===
During the [[Irish Civil War]], [[Irish Republican Army (1922–1969)|Anti-Treaty IRA]] members [[Rory O'Connor (Irish republican)|Rory O'Connor]], [[Liam Mellows]], [[Richard Barrett (Irish republican)|Richard "Dick" Barrett]] and [[Joseph McKelvey]] were executed ex post facto and without trial, just two days into the existence of the [[Irish Free State]]. Despite being imprisoned for over four months, following their deaths the [[3rd Dáil|Third Dáil]] retrospectively approved their executions for a crime that had only been legislated against. Largely, the executions were considered retribution for the assassination of the legislator, Deputy [[Seán Hales]] TD the previous day.

The imposition of retroactive criminal sanctions is prohibited in the subsequent [[Constitution of Ireland|Irish Constitution]], introduced by [[Eamonn De Valera]], in Article 15.5.1°. Retroactive changes of the civil law have also been found to violate the constitution when they would have resulted in the loss in a right to damages before the courts, the [[Supreme Court (Ireland)|Irish Supreme Court]] having found that such a right is a constitutionally protected property right.

===Israel===
[[Israel]] enacted the 1950 [[Nazis and Nazi Collaborators (Punishment) Law]] for the purpose of punishing acts that occurred during the [[Second World War]] and the [[The Holocaust|Holocaust]], when Israel did not exist as a state. The law was used to punish [[Adolf Eichmann]] and others.{{citation needed|date=November 2020}}

===Italy===
Article 25, paragraph 2, of the [[Constitution of Italy|Italian Constitution]], establishing that "nobody can be punished but according to a law come into force before the deed was committed", prohibits indictment pursuant a retroactive law. Article 11 of preliminary provisions to the [[Italian civil code|Italian Civil Code]] and Article 3, paragraph 1, of the Statute of taxpayer's rights, prohibit retroactive laws on principle: such provisions can be derogated, however, by acts having force of the ordinary law; on the contrary, non-retroactivity in criminal law is thought absolute.<ref>{{Cite journal|url=https://www.academia.edu/10805861|title=Irretroattività della norma penale e redazione legislativa|first=Giampiero|last=Buonomo|via=www.academia.edu}}</ref>

===Japan===
Article 39 of the [[constitution of Japan]] prohibits the retroactive application of laws. Article 6 of [[Criminal Code of Japan]] further states that if a new law comes into force after the deed was committed, the lighter punishment must be given.

===Lithuania===
Lithuania has no constitutional prohibition on ''ex post facto'' laws. However, as a signatory of the [[European Convention on Human Rights]] and as a member of the European Union whose [[Charter of Fundamental Rights of the European Union|Charter of Fundamental Rights]] has the effect of law, any retroactive law could still be struck down. Retroactive criminal sanctions are prohibited by Article 2, Part 1 (Chapter 1) of the [[Criminal Code]] of the [[Republic of Lithuania]]. Retroactive administrative sanctions are prohibited by Article 8 of the Administrative Code of the Republic of Lithuania.

Lithuanian lawyer Dainius Žalimas contends that there has been retroactive application of the law on Genocide (and subsequently adopted articles of the Criminal Code) against participants in Soviet repressions against Lithuanian guerilla fighters and their supporters, and gives examples of such decisions. The Article 99 of the Criminal Code of the Republic of Lithuania was introduced only on September 26, 2000, and therefore can't be used in events of 1944–1953.

===Mexico===
According to the first and second paragraphs of the 14th Article of the [[Constitution of Mexico|Mexican Constitution]], retroactive application of the law is prohibited if it is detrimental to a person's rights, but a new law can be applied if it benefits the person.

===Netherlands===
Article 4 of the Law on General Provisions (in effect since 1838) states that "The law has no retroactive effect".<ref>{{cite web|url=https://wetten.overheid.nl/BWBR0001833/2012-01-01|title=Wet algemene bepalingen|first=Ministerie van Binnenlandse Zaken en|last=Koninkrijksrelaties|website=wetten.overheid.nl}}</ref>

Article 1 of [[Dutch Criminal Code|Criminal Law]] states that no act is punishable without a pre-existing law, and that in the case an act was punishable but the law was changed after the criminal act the "most favorable" (to the suspect) of the two laws will apply.<ref>{{cite web|url=https://wetten.overheid.nl/BWBR0001854/2019-11-01/#BoekEerste_TiteldeelI_Artikel1|title=Wetboek van Strafrecht|first=Ministerie van Binnenlandse Zaken en|last=Koninkrijksrelaties|website=wetten.overheid.nl}}</ref>

In [[Burgerlijk Wetboek|Civil Law]] there is no such provision.

===New Zealand===
Section 7 of the Interpretation Act 1999 stipulates that enactments do not have retrospective effect. The [[New Zealand Bill of Rights Act 1990]] also affirms New Zealand's commitment to the [[International Covenant on Civil and Political Rights]] and [[Universal Declaration of Human Rights]], with section 26 preventing the application of retroactive penalties. This is further reinforced under section 6(1) of the current Sentencing Act 2002 which provides, "[p]enal enactments not to have retrospective effect to disadvantage of offender" irrespective of any provision to the contrary.

Section 26 of the Bill of Rights and the previous sentencing legislation, the Criminal Justice Act 1985, caused significant digression among judges when the [[Parliament of New Zealand|New Zealand Parliament]] introduced legislation that had the effect of enacting a retrospective penalty for crimes involving an element of home invasion. Ultimately, the discrepancy was restricted with what some labelled artificial logic in the cases of ''R v Pora'' and ''R v Poumako''.

===Norway===
Article 97 of the [[constitution of Norway|Norwegian Constitution]] prohibits any law to be given retroactive effect. The prohibition applies to both criminal and civil laws, but in some civil cases, only particularly unreasonable effects of retroactivity will be found unconstitutional.<ref>{{cite web |title=Norwegian Supreme Court case 2009/1575 |url=http://www.domstol.no/upload/HRET/saknr2009-1663-plenum.pdf |publisher=domstol.no}}</ref>

===Pakistan===
Article 12 of the [[Constitution of Pakistan of 1962|Constitution of Pakistan]] prohibits any law to be given retroactive effect by stating:<ref>{{cite web|url=http://www.pakistani.org/pakistan/constitution/part2.ch1.html|title=Chapter 1: "Fundamental Rights" of Part II: "Fundamental Rights and Principles of Policy"|website=pakistani.org}}</ref>
* 12.1 – No law shall authorize the punishment of a person:-
* 12.1.a – for an act or omission that was not punishable by law at the time of the act or omission; or
* 12.1.b – for an offence by a penalty greater than, or of a kind different from, the penalty prescribed by law for that offence at the time the offence was committed.

===Philippines===
The 1987 [[Constitution of the Philippines]] categorically prohibits the passing of any ''ex post facto'' law. Article III ([[Bill of rights|Bill of Rights]]), Section 22 specifically states: "No ''ex post facto'' law or [[bill of attainder]] shall be enacted."

However, the [[Cybercrime Prevention Act of 2012|Cybercrime Prevention Act]], which went into effect on October 3, 2012, is criticized for being ''ex post facto''.{{citation needed|date=October 2022}}

===Poland===
Retroactive application of law is prohibited by the Article 3 of the Polish [[civil code]], and the [[legal rule]] prohibiting such retroactive application is commonly memorised as a [[Latin]] sentence ''Lex retro non agit'' ("A law does not apply retroactively"). The said article, however, allows retroactive application of an Act of Parliament if it is expressly understood from its text or purpose.

===Portugal===
Article 18 of the [[Constitution of Portugal|Portuguese Constitution]] forbids the retroactive application of any law the restricts right; article 29 of the Portuguese Constitution forbids retroactive application of criminal law; article 103 forbids the application of retroactive taxes.

===Romania===
Article 15 (2) of the [[Constitution of Romania|Romanian Constitution]] provides that the law shall only act for the future, except for the more favourable criminal or administrative law.

===Russia===
''Ex post facto'' punishment in criminal and administrative law is prohibited by article 54 of the [[Constitution of Russia|Russian Constitution]]; ''ex post facto'' tax laws by article 57 of the constitution. Criminal law which improves the position of the convicted has retroactive force according to article 10 of the [[Criminal Code of Russia|Russian Criminal Code]].

===Spain===
Article 9.3 of the [[Spanish Constitution]] guarantees the principle of non-retroactivity of punitive provisions that are not favorable to or restrictive of individual rights. Therefore, "ex post facto" criminal laws or any other retroactive punitive provisions are constitutionally prohibited.

As well as [[Statute law]] mentioned above, this now also includes '[[Precedent|court-made law]]'. The [[Parot doctrine (Spain)|Parot doctrine]], in which terrorists were denied the right (enshrined in a 1973 Statute) to earn a reduction in the length of their sentences by a Spanish court ruling in 2006 was judged by the [[European Court of Human Rights]] to be contrary to relevant articles on [[European Convention on Human Rights#Article 7 – retroactivity|retroactivity]] & [[European Convention on Human Rights#Article 5 – liberty and security|liberty and security]] in 2013.

===South Africa===
Section 35(3) of the [[South African Bill of Rights]] prohibits ''ex post facto'' criminal laws, except that acts which violated international law at the time they were committed may be prosecuted even if they were not illegal under national law at the time. It also prohibits retroactive increases of criminal punishments.

===Sweden===
In [[Sweden]], retroactive penal sanctions and other retroactive legal effects of criminal acts due the State are prohibited by chapter 2, section 10 of the [[Constitution of Sweden#Instrument of Government|Instrument of Government]] (''Regeringsformen''). Retroactive taxes or charges are not prohibited, but they can have retroactive effect reaching back only to the time when a new tax bill was proposed by the government. The retroactive effect of a tax or charge thus reaches from that time until the bill is passed by the parliament.

As the [[Swedish Act of Succession]] was changed in 1979, and the throne was inherited regardless of sex, the inheritance right was withdrawn from all the descendants of [[Charles XIV John]] (king 1818–44) except the current king [[Carl XVI Gustaf]]. Thereby, the heir-apparent title was transferred from the new-born [[Prince Carl Philip]] to his older sister [[Crown Princess Victoria]].

The [[Riksdag|Swedish Riksdag]] voted in 2004 to abolish [[inheritance tax]] by January 1, 2005. However, in 2005 they retro-actively decided to move the date to December 17, 2004. The main reason was abolishing inheritance tax for the many Swedish victims of the [[2004 Indian Ocean earthquake]], which took place on December 26.{{citation needed|date=March 2019}}

===Turkey===
''Ex post facto'' punishment is prohibited by Article 38 of the [[Constitution of Turkey]]. It states:
* c1. No one shall be punished for any act which does not constitute a criminal offence under the law in force at the time committed; no one shall be given a heavier penalty for an offence other than the penalty applicable at the time when the offence was committed.
* c2. The provisions of the above paragraph shall also apply to the statute of limitations on offences and penalties and on the results of conviction.
Thus, the article does not prohibit ''in mitius'' laws, i.e. cases wherein the retroactive application benefits the accused person.

===Ukraine===
Article 58 of the [[Constitution of Ukraine]] says: "Laws and other regulatory acts shall have no retroactive force except where they mitigate or nullify the responsibility of a person. No one shall bear responsibility for acts that, at the time they were committed, were not deemed by law to be an offence."

===United Kingdom===
In the [[United Kingdom]], ''ex post facto'' laws are permitted by virtue of the doctrine of [[parliamentary sovereignty]]. Historically, all [[Act of Parliament|acts of Parliament]] before 1793 were ''ex post facto'' legislation, inasmuch as their date of effect was the first day of the session in which they were passed. This situation was rectified by the [[Acts of Parliament (Commencement) Act 1793]].

Some laws are still passed retrospectively: e.g., the Pakistan Act 1990 (by which the United Kingdom amended its legislation consequent to the [[Commonwealth of Nations]] having re-admitted Pakistan as a member) was one such law; despite being passed on 29 June 1990, section 2 subsection 3 states that "This Act shall be deemed to have come into force on 1st October 1989", nine months before it was enacted.<ref name=NA_PA1990 >{{cite web |url=http://www.legislation.gov.uk/ukpga/1990/14/section/2 |title=Pakistan Act 1990 |publisher=Government of the United Kingdom |access-date=17 September 2010}}</ref>

Retrospective ''criminal'' laws are prohibited by Article 7 of the [[European Convention on Human Rights]], to which the United Kingdom is a signatory, but some legal authorities have stated their opinion that parliamentary sovereignty takes priority even over this.<ref>[[Tom Denning, Baron Denning|Lord Denning]] in ''Macarthys Ltd v Smith'' [1979] ICR 785 at p. 789, quoted in {{cite book |last1=Steiner |first1=Josephine |first2=Lorna |last2=Woods |first3=Christian |last3=Twigg-Flesner |title=EU Law |edition=9th |year=2006 |publisher=Oxford University Press |location=Oxford, New York |isbn=978-0-19-927959-3 |chapter=Section 4.4.2: Effect of the European Communities Act 1972, s.2(1) and (4) |quote=If the time should come when our Parliament deliberately passes an Act with the intention of repudiating the Treaty or any provision in it or intentionally of acting inconsistently with it – and says so in express terms – then ... it would be the duty of our courts to follow the statute of our Parliament. |page=79}}</ref><ref>{{cite web |url=https://publications.parliament.uk/pa/cm200405/cmselect/cmeuleg/38-xiv/5020802.htm |title=Select Committee on European Scrutiny Minutes of Evidence: Examination of Witnesses (Questions 229-239): Rt hon Jack Straw MP and Mr David Frost |access-date=2008-01-09 |first=Jack |last=Straw |author-link=Jack Straw |date=2005-02-08 |work=House of Commons Publications |quote=I think your Committee will be familiar with what Lord Denning, then Master of the Rolls, said in McCarthy v Smith: 'If the time should come when our Parliament deliberately passes an Act with the intention of repudiating the Treaty or any provision of it or with the intention of acting inconsistently with it—it says so in express terms—I should have thought it would be the duty of our courts to follow the statute in our Parliament.' That much is clear. Other consequences would follow in those circumstances, which arise from our signature on the Vienna Convention on the Law of Treaty, Article 27, which says that you have to respect the international obligations into which you have entered.}}</ref> For example, the [[War Crimes Act 1991]] created an ''ex post facto'' jurisdiction of British courts over [[war crime]]s committed during the [[World War II|Second World War]]. Another important example of a case which shows the doctrine of parliamentary supremacy in action is in relation to ''[[Burmah Oil Co Ltd v Lord Advocate]]'', where the decision of the courts was overridden with retrospective effect by the [[War Damage Act 1965]], which changed the law on compensation resulting from [[scorched earth]] actions in Burma during the war. More recently, the [[Police (Detention and Bail) Act 2011]] retroactively overrode a controversial court judgment resulting from an error in the drafting of the [[Police and Criminal Evidence Act 1984]] that would potentially have invalidated thousands of criminal convictions.

Another example of an ''ex post facto'' criminal law in the UK is the [[Criminal Justice Act 2003]]. This law allows people acquitted of murder and certain other serious offences to be retried if there is "new, compelling, reliable and substantial evidence" that the acquitted person really was guilty. This Act applies retroactively and can be used to re-prosecute people who were acquitted before it came into force in 2005, or even before it was passed in 2003. As a result, two of the defendants who were acquitted in the [[murder of Stephen Lawrence]] were allowed to be retried, even though this murder occurred in 1993 and the defendants had been acquitted in 1996. Many people have criticized the Criminal Justice Act because of its essential abolition of prohibition against both ex post facto and [[double jeopardy]] laws.<ref>{{cite web|url=https://www.telegraph.co.uk/news/uknews/crime/8982608/Stephen-Lawrence-murder-change-in-double-jeopardy-law-allowed-Gary-Dobson-prosecution.html |archive-url=https://ghostarchive.org/archive/20220112/https://www.telegraph.co.uk/news/uknews/crime/8982608/Stephen-Lawrence-murder-change-in-double-jeopardy-law-allowed-Gary-Dobson-prosecution.html |archive-date=2022-01-12 |url-access=subscription |url-status=live|title=Stephen Lawrence murder: change in double jeopardy law allowed Gary Dobson prosecution|first=Tom|last=Whitehead|date=3 January 2012|work=[[The Daily Telegraph]]}}{{cbignore}}</ref>

Taxation law has on multiple occasions been changed to retrospectively disallow [[tax avoidance]] schemes.<ref>{{cite news| url=https://news.bbc.co.uk/1/hi/business/8496921.stm | work=BBC News | title=Will retrospective taxes affect us all? | date=5 February 2010 | access-date=2 May 2010}}</ref>  The most significant example known concerns double-taxation treaty arrangements where the [[Finance Act 2008]] with [[BN66]] retrospectively amended 1987 legislation, creating large tax liabilities for 3,000 people where no liability existed before.

===United States===
[[Thomas Jefferson]], one of the [[Founding Fathers of the United States]], stated in 1813 that:
{{blockquote|The sentiment that ''ex post facto'' laws are against natural right is so strong in the United States, that few, if any, of the State constitutions have failed to proscribe them. ...The federal constitution indeed interdicts them in criminal cases only; but they are equally unjust in civil as in criminal cases, and the omission of a caution which would have been right, does not justify the doing what is wrong. Nor ought it to be presumed that the legislature meant to use a phrase in an unjustifiable sense, if by rules of construction it can be ever strained to what is just.| [[Thomas Jefferson]] | [[q:Thomas Jefferson#Letter to Isaac McPherson (1813)|Letter to Isaac McPherson]], August 13, 1813 }}
[[United States Congress|Congress]] is prohibited from passing ''ex post facto'' laws by clause 3 of [[Article One of the United States Constitution|Article I]], [[Article One of the United States Constitution#Section 9: Limits on Federal power|Section 9]] of the [[United States Constitution]]. The states are prohibited from passing ''ex post facto'' laws by clause 1 of [[Article One of the United States Constitution|Article I]], [[Article 1 Section 10|Section 10]]. This is one of the relatively few restrictions that the United States Constitution made to both the power of the federal and state governments before the [[Fourteenth Amendment to the United States Constitution|Fourteenth Amendment]].  Over the years, however, when deciding ''ex post facto'' cases, the [[Supreme Court of the United States|United States Supreme Court]] has referred repeatedly to its ruling in ''[[Calder v. Bull]]'', in which Justice [[Samuel Chase]] held that the prohibition applied only to criminal matters, not civil matters, and established four categories of unconstitutional ''ex post facto'' laws.<ref>''[[Calder v. Bull]]'', {{ussc|3|386|1798}}.</ref> The case dealt with the Article I, Section 10, prohibition on ''ex post facto'' laws, because it concerned a Connecticut state law.

As a result of ''Calder v. Bull'', several retroactive taxes have been passed by the US Congress, starting with the 1913 Revenue Act, which imposed the first income tax. By 1935, prohibitions on retroactive taxation had been declared "dead." In 1938, the US Supreme Court claimed the standard on retroactive taxation was "retroactive application is so harsh and oppressive as to transgress the constitutional limitation." In practice, this has resulted in virtually all retroactive taxes being upheld, and in one case a 1993 revision of tax law that applied retroactively to 1984 was upheld.<ref>{{cite web | url=https://www.heritage.org/taxes/report/retroactive-tax-increases-and-the-constitution | archive-url=https://web.archive.org/web/20171030205203/http://www.heritage.org/taxes/report/retroactive-tax-increases-and-the-constitution | url-status=unfit | archive-date=October 30, 2017 | title=Retroactive Tax Increases and the Constitution }}</ref><ref>{{cite web | url=https://www.jdsupra.com/legalnews/retroactive-tax-laws-but-they-can-t-do-3996868/ | title=Retroactive Tax Laws – but They Can't do That, Can They? }}</ref>

Not all laws with retroactive effects have been held to be unconstitutional. One current U.S. law that has a retroactive effect is the [[Adam Walsh Child Protection and Safety Act]] of 2006. This law imposes new registration requirements on convicted [[sex offenders]] and also applies to offenders whose crimes were committed before the law was enacted.<ref>{{cite web|url=https://www.congress.gov/bill/109th-congress/house-bill/4472/text|title=Text - H.R.4472 - 109th Congress (2005-2006): Adam Walsh Child Protection and Safety Act of 2006|date=July 27, 2006|website=congress.gov}}</ref> The U.S. Supreme Court ruled in ''[[Smith v. Doe]]'' (2003) that requiring sex offenders to register their whereabouts at regular intervals, and the posting of personal information about them on the Internet, do not violate the constitutional prohibition against ''ex post facto'' laws, because these laws do not impose any kind of punishment.<ref>''[[Smith v. Doe]]'', {{ussc|538|84|2003}}.</ref><ref>{{cite web|url=https://law.onecle.com/constitution/article-1/59-ex-post-facto-laws.html|title=Ex Post Facto Laws - United States Constitution|website=law.onecle.com}}</ref>

In ''Starkey v. Oklahoma Department of Corrections'', the [[Oklahoma Supreme Court|Supreme Court of the State of Oklahoma]] found the Oklahoma Sex Offender Registration Act, or SORA, to be punitive in nature, if not in intent. While the law in question had been ruled as not being retroactive in nature, the Oklahoma Department of Corrections had been applying the new legislation retroactively. The court found that "the Department's retroactive application of the level assignment provisions of 57 O.S. Supp. 2007, 582.1 – 582.5, as amended, violates the ex post facto clause."<ref>''[https://law.justia.com/cases/oklahoma/supreme-court/2013/109556.html Starkey v. Oklahoma Department Of Corrections]'', 2013 OK 43 (2013);  [http://www.oscn.net/applications/oscn/DeliverDocument.asp?CiteID=470336 OSCN Document]</ref>

Controversy has also arisen with regard to [[sexually violent predator laws|sexually violent predator (SVP) laws]], which allow the indefinite commitment of a person with a mental abnormality which predisposes them to molest children. This issue arose in the case ''[[Kansas v. Hendricks]]''.<ref name="Hendricks">''[[Kansas v. Hendricks]]'', {{ussc|521|346|1997}}.</ref> In ''Hendricks'', a man with a long history of sexually molesting children was scheduled to be released from prison shortly after the enactment of [[Kansas]]'s SVP act. Rather than being released, he was committed on the grounds that he had a mental abnormality. Hendricks contested the law on ''ex post facto'' and double jeopardy grounds. The [[Kansas Supreme Court|Supreme Court of Kansas]] invalidated the Act, but the [[Supreme Court of the United States]] reversed the decision and ruled that the law was constitutional on the basis that the law did not impose a criminal punishment.<ref name="Hendricks" />

Another example is the [[Domestic Violence Offender Gun Ban]], where firearms prohibitions were imposed on those convicted of misdemeanor domestic-violence offenses and on subjects of restraining orders (which do not require criminal conviction). These individuals can now be sentenced to up to ten years in a [[Federal Bureau of Prisons|federal prison]] for possession of a firearm, regardless of whether the weapon was legally possessed when the law was passed.<ref>{{Uscsub|18|922|g|8}}, {{Uscsub2|18|922|g|9}}, and {{Uscsub2|18|924}}.</ref> The law has been legally upheld because it is considered regulatory, not punitive; it is a [[status offense]].<ref>''[[United States v. Emerson]]'', 270 F.3d 203 (5th Cir. 2001).</ref>

Another example is the [[Copyright Term Extension Act]], which was retroactive since it affected both new works and existing ones, but it was upheld by decision [[Eldred v. Ashcroft]]. Also, the [[Uruguay Round Agreement Act]], which restored copyright in foreign works, removing them from the [[public domain]], was upheld by another decision, [[Golan v. Holder]].{{cn|date=November 2025}}

The US military also recognizes ex post facto law. [[Common law]] states that Courts-martial will not enforce an ex post facto law, including increasing amount of pay to be forfeited for specific crimes. (See [https://www.ucmjdefense.com/resources/army-jag-school-criminal-law-deskbook-volume/military-justice-system-overview/6214-2.html United States v. Gorki 47 M.J. 370]).

Finally, in ''[[Calder v. Bull]]'', the court expressly stated that a law that "mollifies" a criminal act was merely retrospective, and was not an ''ex post facto'' law.<ref>''Calder'', 3 U.S.</ref> Scholars have argued that, as a historical matter, the phrase ''ex post facto'' referred to civil as well as criminal laws.<ref>{{cite journal|last1=Zoldan|first1=Evan|url=https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2469141|title=The Civil Ex Post Facto Clause|ssrn=2469141|journal=Wisconsin Law Review|date=2015}}</ref>

In [[United States administrative law|administrative law]], federal agencies may apply their rules retroactively if Congress has authorized them to; otherwise, retroactive application is generally prohibited. Retroactive application of regulations is disfavored by the courts for several reasons. The courts uphold retroactive regulation where Congress has expressly granted such retroactive power to the agency, as they did in ''[[Bowen v. Georgetown University Hospital]]''.<ref>''Bowen v. Georgetown University Hospital'', {{ussc|488|204|1988}}.</ref>

The rules as they relate to the effects of ''ex post facto'' upon the [[United States Federal Sentencing Guidelines|U.S. Federal Sentencing Guidelines]] can be found in {{ussg|1b1.11}}.

See also ''[[Bouie v. City of Columbia]]'', ''[[Rogers v. Tennessee]]'', ''[[Stogner v. California]]'', ''[[Republic of Austria v. Altmann]]'', ''[[James Bamford]]'' and ''[[Samuels v. McCurdy]]''.

=== Vietnam ===
''Ex post facto'' laws is defined in Article 152, 2015 Law on Promulgation of Legal Documents:

# Only in cases of '''extreme necessity to ensure the common good of society''', to '''exercise the rights and interests''' of organizations and individuals prescribed in laws and resolutions of the National Assembly, legal documents of central government rules are retroactive.
# The retroactive effect is prohibited in the following cases:  a) Impose legal liability for acts that at the time of committing such acts the law does not stipulate liability;  b) Impose higher legal liability.
# Legislative documents of People's Councils, People's Committees at all levels, local governments in special administrative-economic units are not retroactive.

There has been no case that new law stated it has a retroactive effect. But the second item of this Article has been widely used in court system (''in mitius'' laws'')''.

==Treatment by international organizations and treaties==

===International criminal law===
In [[international criminal law]], the [[Nuremberg trials]] prosecuted [[war crime]]s and [[crimes against humanity]] perpetrated in World War II. Although the [[Nuremberg Charter]], the [[procedural law]] under which the trials were held, postdated [[V-E Day]], the tribunal rejected the defence that the criminal law was ''ex post facto'', arguing it derived from earlier treaties like the [[Hague Conventions of 1899 and 1907]]. The [[International Criminal Court]] established in 2002 that it cannot prosecute crimes committed before 2002.

===Universal Declaration of Human Rights and related treaties===
Article 11, paragraph 2 of the [[Universal Declaration of Human Rights]] provides that no person be held guilty of any criminal law that did not exist at the time of offence nor suffer any penalty heavier than what existed at the time of offence. It does however permit application of either domestic or international law.

Very similar provisions are found in Article 15, paragraph 1 of the [[International Covenant on Civil and Political Rights]], replacing the term "penal offence" with "criminal offence". It also adds that if a lighter penalty is provided for after the offence occurs, that lighter penalty shall apply retroactively. Paragraph 2 adds a provision that paragraph 1 does not prevent trying and punishing for an act that was criminal according to the general principles of law recognized by the community of nations. Specifically addressing the use of the death penalty, article 6, paragraph 2 provides in relevant part that a death sentence may only be imposed "for the most serious crimes in accordance with the law in force at the time of the commission of the crime".

===African Charter on Human and Peoples' Rights===
Article 2, paragraph 7 of the [[African Charter on Human and Peoples' Rights]] provides in part that "no one may be condemned for an act or omission which did not constitute a legally punishable offence at the time it was committed. No penalty may be inflicted for an offence for which no provision was made at the time it was committed."

===American Declaration of the Rights and Duties of Man===
Article 25 of the [[American Declaration of the Rights and Duties of Man]] provides in part that "[n]o person may be deprived of his liberty except in the cases and according to the procedures established by pre-existing law." The right to be tried in accordance to "pre-existing law" is reiterated in article 26.

===Arab Charter on Human Rights===
Article 15 of the [[Arab Charter on Human Rights]] provides that "[n]o crime and no penalty can be established without a prior provision of the law. In all circumstances, the law most favorable to the defendant shall be applied."

===European Convention on Human Rights===
Effectively all European states (except [[Belarus]]), including all [[European Union]] and [[European Economic Area]] states, are bound by the [[European Convention on Human Rights]]. [[Article 7 of the European Convention on Human Rights|Article 7 of the Convention]] mirrors the language of both paragraphs of Article 15 of the International Covenant on Political and Civil Rights, with the exception that it does not include that a subsequent lighter penalty must apply.

==Grammatical form and usage==
The ''[[Digest (Roman law)|Digesta Iustiniani]]'' (15.3.10.8.3, 20.1.22.pr2) ("Digest of [[Justinian I|Justinian]]") contains the two-word phrase ''ex postfacto'': "out of a postfactum" (an after-deed), or more naturally, "from a law passed afterward". This same work, however, also makes use of the three-word phrase ''ex post facto'', (2.14.17.4.2, 4.6.17.1.1, ''passim''), suggesting that ''post'' might best be understood as an adverb.  Other adverbial usages of ''post'' include the [[Ancient Rome|Classical Roman]] author and senator [[Marcus Tullius Cicero]] employing phrases such as ''multis post annis'' (''[[De re publica|De Re Publica]]'' 2.5.8 and elsewhere).  Thus, ''ex post facto'' or ''ex postfacto'' is natively an adverbial phrase, a usage demonstrated by the sentence "He was convicted ''ex post facto'' (from a law passed after his crime)." The law itself would rightfully be a ''lex postfacta'' in Latin, although English generally uses the phrase "an ex post facto law".

In Poland the phrase ''[[:pl:Lex retro non agit|lex retro non agit]]'' ("the law does not operate retroactively") is used.<ref>{{cite book|last=Mattila|first=Heikki E. S.|author2=Christopher Goddard|title=Comparative Legal Linguistics|publisher=Ashgate Publishing|year=2006|page=154|isbn=978-0-7546-4874-1}}</ref>

==See also==
{{Portal|Law}}
* [[A priori and a posteriori|''A priori'' and ''a posteriori'']]
* {{annotated link|Acts of Parliament (Commencement) Act 1793}}
* ''[[Ex ante]]''
* ''[[Nulla poena sine lege]]'' – the principle that no one may be punished for an act which is not against the law
* [[Richard Roose]]
* [[Rokotov–Faibishenko case]]
* [[Grandfather clause]], which specifically allows things allowed before a law
* [[Bill of attainder]], a legislative act which convicts and sentences a person without trial

==References==
{{Reflist|30em}}

==External links==
{{wiktionary|ex post facto|retroactivity}}
* {{Cite NIE|wstitle=Ex Post Facto|short=x}}

{{Criminal procedure (investigation)}}
{{Authority control}}

{{DEFAULTSORT:Ex Post Facto Law}}
[[Category:Ex post facto law| ]]
[[Category:Brocards (law)]]
[[Category:Constitutional law]]
[[Category:Criminal procedure]]
[[Category:Latin legal terminology]]

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