What is the post facto law?
Asked by: Zella Fay | Last update: February 17, 2026Score: 5/5 (19 votes)
An ex post facto law (Latin for "after the fact") is a law that retroactively changes the legal consequences of actions committed before the law was enacted, making an act a crime that wasn't, increasing punishment for a past act, or altering rules of evidence to make conviction easier. The U.S. Constitution explicitly forbids both the federal government and states from passing such laws in criminal matters, ensuring people aren't punished for something that was legal when they did it.
What is a post-facto law?
An ex post facto law, named using the Latin phrase for after the fact, is a law that imposes criminal liability or increases criminal punishment retroactively. 1. E.g., Locke v. New Orleans, 71 U.S. 172, 173 (1867).
What does post facto actually mean?
The Latin phrase ex post facto means “from a thing done afterward.” In law, it refers to a criminal statute that retroactively punishes conduct that was legal at the time it was committed.
Can Congress pass an ex post facto law?
Article I, Section 9, Clause 3: No Bill of Attainder or ex post facto Law shall be passed.
What are the three things that make up an ex post facto law?
There are three categories of ex post facto laws: those “which punish[ ] as a crime an act previously committed, which was innocent when done; which make[ ] more burdensome the punishment for a crime, after its commission; or which deprive[ ] one charged with crime of any defense available according to law at the time ...
What is Ex Post Facto? [legal terminology explained]
Why is ex post facto illegal?
In most cases, this means a trial. Similarly, the prohibition against ex post facto laws reinforces the idea that the government cannot punish someone retroactively for an action they took that was lawful at the time. In combination, the prohibitions protect citizens against potential abuses of government power.
What happens if an ex post facto law is passed?
In criminal law, it may 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 ...
Can laws be enforced retroactively?
Adjudications are by their nature retroactive applications of the law. That is, a judicial body necessarily determines whether a litigant's past events violated a law. However, retroactive application of statutes or rules are generally disfavored.
Is it ethical to create post facto laws?
In this case, Justice Chase noted that no people with a sense of reason and justice would entrust the government with the power to pass ex post facto laws, because any such act by a legislature would offend natural law even if it were not prohibited by the Constitution.
Can ex post facto laws be justified?
Ex post facto laws violate the constitution.
Article I, section 10, of the United States Constitution and article I, section 11, of the Minnesota Constitution prohibit the state from enacting ex post facto laws.
What is another word for post facto?
from or by subsequent action; retroactively; subsequently; retrospectively.
What is the ex post facto process?
Ex post facto study or after-the-fact research is a category of research design in which the investigation starts after the fact has occurred without interference from the researcher.
Are there any exceptions to the post facto rule?
Constitutional prohibition: Ex-post facto laws are prohibited for both state and federal governments. Exceptions: Some civil laws may be allowed under specific conditions.
What does article 7 of the U.S. Constitution say?
Article VII of the U.S. Constitution is about the ratification process, stating that nine of the thirteen states needed to approve it through special state conventions for the Constitution to become the law of the land, replacing the Articles of Confederation. It established the conditions for the new government to take effect and included the date the Constitution was signed (September 17, 1787).
Is a retroactive law unconstitutional?
In the American legal system, the legality of a retroactively applied law depends largely on whether the law would improve or worsen the plight of the individuals it would affect. If it's the latter, the law is known as an “ex post facto” law and is prohibited by the United States and Illinois constitutions.
How do ex post facto laws protect individual rights?
Protects individuals from prosecution for acts that were not criminal at the time that they were committed, or from changes in the penalties for acts.
What does the 27th Amendment actually say?
The 27th Amendment to the U.S. Constitution says that no law varying the compensation for Senators and Representatives shall take effect until an election of representatives has intervened, meaning Congress can't give itself a pay raise that takes effect immediately; they have to wait until after the next election, allowing voters to decide if they approve. It was originally proposed in 1789 by James Madison but wasn't ratified until 1992, making it the last ratified amendment, with a long history due to its lack of a time limit for ratification.
Why are post facto laws generally prohibited?
Such laws are generally deemed unfair, because, in the nature of the case, the person, or persons, involved in the behavior to which such a law relates, can have had no notice, when the behavior took place, of such an after-made law which applies to it. The unfairness varies, however, from case to case.
What is de facto illegal?
De Facto is a legal term meaning "in fact" or "in reality", which is used to qualify many legal concepts, even when the formal legal requirements have not been met. De facto law refers to a legal practice or formality that is not specifically enumerated by law.
What two things can Congress not pass?
No Bill of Attainder or ex post facto Law shall be passed. No Capitation, or other direct, Tax shall be laid, unless in Proportion to the Census or enumeration herein before directed to be taken. No Tax or Duty shall be laid on Articles exported from any State.
What are some examples of ex post facto laws?
If a law was passed the following week to increase the penalty to a year in jail, and the driver received this sentence, this would be an example of an ex post facto law because the penalty increased and was applied retroactively after the crime was committed.
What is the law does not apply retroactively?
Non-retroactivity is the legal principle that laws do not apply retroactively and ex post facto laws are forbidden. This principle may be applied to judicial decisions as well as statutory law.
What does bill of attainder mean?
A bill of attainder is legislation that imposes punishment on a specific person or group of people without a judicial trial.
What law makes an act illegal after the fact?
Ex post facto laws, regarded as tools of oppression when the U.S. Constitution was written, were banned in Article I, section 9, of the Constitution, where they are excluded from the powers of Congress, and in Article I, section 10, where the exclusion is applied to state legislatures.
What is an ex post facto law applies legal consequences to?
An ex post facto law applies legal consequences to actions that were committed before the law was enacted, meaning individuals cannot be punished for actions that were legal at the time they were performed. These laws are prohibited by the U.S. Constitution to ensure fairness in legal proceedings.