Ex post facto law

An ex post facto law (from the Latin for "after the fact") or retroactive law, is a law that retroactively changes the legal consequences of acts committed or the legal status of facts and relationships that existed prior to the enactment of the law. In reference to criminal law, it may criminalize actions that were legal when committed; or it may aggravate a crime by bringing it into a more severe category than it was in at the time it was committed; or it may change or increase the punishment prescribed for a crime, such as by adding new penalties or extending terms; or it may alter the rules of evidence in order to make conviction for a crime more likely than it would have been at the time of the action for which a defendant is prosecuted. Conversely, a form of "ex post facto" law commonly known as an amnesty law may decriminalize certain acts or alleviate possible punishments (for example by replacing the death sentence with life-long imprisonment) retroactively.

A law may have an "ex post facto" effect without being technically ex post facto. For example, when a law repeals a previous law, the repealed legislation no longer applies to the situations it once did, even if such situations arose before the law was repealed. The principle of prohibiting the continued application of these kinds of laws is also known as "Nullum crimen, nulla poena sine praevia lege poenali".

Generally speaking, "ex post facto" penal laws are seen as a violation of the rule of law as it applies in a free and democratic society. Most common law jurisdictions do not permit retroactive criminal legislation, though some have suggested that judge-made law is retroactive as a new precedent applies to events that occurred prior to the judicial decision. In some nations that follow the Westminster system of government, such as the United Kingdom, "ex post facto" laws are technically possible as the doctrine of parliamentary supremacy allows parliament to pass any law it wishes. However, in a nation with an entrenched bill of rights or a written constitution, "ex post facto" legislation may be prohibited.

Ex post facto is the uncomplimentary characterization of law and legislation that applies retroactively (i.e. "from a thing done afterward").

"Ex post facto" laws around the world


Australia has no strong constitutional prohibition on "ex post facto" laws, although narrowly retroactive laws might violate the constitutional separation of powers principle. Australian courts normally interpret statutes with a strong presumption that they do not apply retroactively.

Retroactive 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 (see Bottom of the harbour tax avoidance).


According to the 5th Article, XXXVI of Brazilian Constitution, "ex post facto" laws are prohibited in subject of acquired rights, perfect juridicly acts and "res judicata". Like France, there is an exception, when retroactive criminal laws benefits the accused person.and or doomed


In Canada, "ex post facto" criminal laws are constitutionally prohibited by 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 a conviction, the convicted person is entitled to the lesser punishment. However, it is possible for any of the provincial parliaments to create such a law by using the authority found in section 33 of the Charter (commonly referred to as the "notwithstanding clause"), as this section permits legislation to override certain provisions of the Charter, including section 11.


Finland has used "ex post facto" legislature in 1945, after the World War Two on the trial of the war responsibilities in Finland. A law which made the pre-war politics criminal was passed in order to get the leaders nominated by Stalin sentenced. Generally ex post facto jurisprudence is considered violating the Romano-German judicial system, and are banned by the Constitution of Finland. Still, ex post facto laws may be used in civil cases, especially concerning to vehicle taxes.


The expression "Ex post facto law" translates to "loi rétroactive" in French. In France, any "ex post facto" criminal law may be applied only if the retroactive application benefits the accused person (called retroactivity "in mitius"). An example of this rule would be a case where a weaker sentence is now applicable but was not previously applicable. See also the Declaration of the Rights of Man and of the Citizen.


Article 103 of the German basic law requires that an act may only be punished if it has already been punishable by law at the time it was committed (specifically: by "written" law, Germany following civil law).

Some scholars assert that the Nuremberg Trials following World War II were based on "ex post facto" law, because the Allies did not negotiate the London Charter, defining crimes against humanity and creating 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.


In India without using the expression "Ex post facto law" the underlying principle has been adopted in the Article 20 (1) of the Indian Constitution in the following words:

"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."


Article 28I of the Indonesian constitution prohibits trying citizens under retroactive laws in any circumstance. This was tested in 2004 when the conviction of one of the Bali bombers under retroactive anti-terrorist legislation was quashed.


"Ex post facto" laws, in all contexts, are prohibited by Article 169 (Chapter 11) of Iran's constitution.


Article 25, paragraph 2, of the 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 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.


The imposition of retroactive criminal sanctions is prohibited by Article 15.5.1° of the constitution of the Republic of Ireland. 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 Irish Supreme Court having found that such a right is a constitutionally protected property right.


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

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 ICCPR and UNDHR with s 26 preventing the application of retroactive penalties. This is further reinforced under s 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 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.


Article 97 of the Norwegian constitution prohibits any law to be given retroactive effect.


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

outh Africa

Prohibited in criminal law by clause 35.(3)(l) of the Constitution of the Republic of South Africa; an exception exists for offenses which were illegal under international law at the time of commission.


In Sweden, retroactive penal sanctions and other retroactive legal effects of criminal acts due the State are prohibited by chapter 2, article 22, point 5 of the 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.


"Ex post facto" punishment is prohibited by Article 38 of the Constitution of Turkey.

United Kingdom

In the United Kingdom, "ex post facto" laws are strictly frowned upon, but are permitted by virtue of the doctrine of parliamentary sovereignty. Historically, all 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.

"Ex post facto" criminal laws are prohibited by Article 7 of the European Convention on Human Rights, to which the United Kingdom is a signatory, but parliamentary sovereignty, in theory, takes priority even over this.

United States

In the United States, ex post facto laws are prohibited in federal law by Article I, of the U.S. Constitution and in state law by section 10. Over the years, when deciding "ex post facto" cases, the United States Supreme Court has referred repeatedly to its ruling in the Calder v. Bull case of 1798, in which Justice Chase established four categories of unconstitutional "ex post facto" laws. The case dealt with Article I, section 10, since it dealt with a Connecticut state law.

However, not all laws with "ex post facto" effects have been found to be unconstitutional. One current U.S. law that has an "ex post facto" effect is the Adam Walsh Child Protection and Safety Act of 2006. This law, which imposes new registration requirements on convicted sex offenders, gives the U.S. Attorney General the authority to apply the law retroactively. [cite web |url=http://thomas.loc.gov/cgi-bin/query/z?c109:H.R.4472: |title=Library of Congress text of H.R.4472] The U.S. Supreme Court ruled in "Smith v. Doe" (2003) that forcing sex offenders to register their whereabouts at regular intervals and the posting of personal information about them on the Internet does not violate the constitutional prohibition against "ex post facto" laws, because compulsory registration of offenders who completed their sentences before new laws requiring compliance went into effect does not constitute a punishment. [cite web |url=http://law.onecle.com/constitution/article-1/59-ex-post-facto-laws.html |title=Ex Post Facto Laws]

Another example is the so-called Lautenberg law where firearms prohibitions were imposed on those convicted of misdemeanor domestic violence offenses and subjects of restraining orders (which do not require a criminal conviction). These individuals can now be sentenced to up to 10 years in a federal prison for possession of a firearm, regardless of whether or not the weapon was legally possessed at the time the law was passed. Among those that it is claimed the law has affected is a father who was convicted of a misdemeanor of child abuse despite claims that he had only spanked his child, since anyone convicted of child abuse now faces a lifetime firearms prohibition. The law has been legally upheld because it is considered regulatory, not punitive - it is a status offense.

Finally, Calder v. Bull expressly stated that a law that "mollifies" a criminal act was merely retrospective and not an "ex post facto" law.

A large "exception" to the ex post facto prohibition can be found in administrative law, as federal agencies may apply their rules retroactively if Congress has authorized them to do so. Retroactive application is disfavored by the courts for a number of reasons, [cite web |url=http://caselaw.lp.findlaw.com/scripts/getcase.pl?navby=CASE&court=US&vol=488&page=204|title=Bowen v. Georgetown University Hospital] but Congress may grant agencies this authority through express statutory provision. Furthermore, when an agency engages in adjudication, it may apply its own policy goals and interpretation of statutes retroactively, even if it has not formally promulgated a rule on a subject.

European Convention on Human Rights

Most European nations, and all European Union nations, are bound by the European Convention on Human Rights. Article 7 of the convention prohibits "ex post facto" criminal laws subject to two exceptions. It also prohibits a heavier penalty being imposed than was applicable at the time when an act was committed. The exceptions are:

*Acts illegal under international law at the time of their commission.
*Acts criminal according to "the general principles of law recognized by civilized nations".


*"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, Letter to Isaac McPherson, August 13th, 1813)

Grammatical form and usage

To students of Latin, this phrase does not appear to make sense, as it consists of the preposition "ex", the preposition "post", and a noun with the wrong grammatical case to agree with "post". Indeed, the Latin for this phrase is actually two words, "ex postfacto", literally, "out of a postfactum (an after-deed)", or more naturally, "from a law passed afterward".

Therefore, "ex post facto" or "ex postfacto" is natively an adverbial phrase, a usage demonstrated by the sentence "He was convicted "ex post facto" ("i.e"., from a law passed after his crime)"." The law itself would rightfully be a "postfactum" law ("lex postfacta"); nevertheless, despite its redundant or circular nature, the phrase "an ex post facto law" is used.

In Poland the phrase "lex retro non agit" ("the law does not operate retroactively") is often used. [cite book|last=Mattila|first=Heikki E. S.|coauthors=Christopher Goddard|title=Comparative Legal Linguistics|publisher=Ashgate Publishing|date=2006|pages=p.154|isbn=9780754648741]

ee also

* Nulla poena sine lege - the principle that no one may be punished for an act which is not against the law.
* Latin phrases


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