Ex Post Facto Defined

What is Ex Post Facto Law?

An Ex Post Facto law is a retroactive law that ultimately changes the legal status or consequences of actions committed or relationships that may have existed prior to the formal enactment of the law. In criminal law, for example, an Ex Post Facto law may criminalize actions that were deemed illegal when committed; or it may alter the punishments attached to a conviction by bringing the charges into a more severe category than what was present when the act was committed. Furthermore, an Ex Post Facto law, in reference to criminal law, may alter the punishment prescribed for the specific crime; Ex Post Facto law may add new penalties or extend the terms that would commonly be attached to the crime.

Ex Post Facto law may also alter the rules of evidence to make a conviction for a crime more likely. This function of Ex Post Facto law can also be contrasted by amnesty law, which is a form of Ex Post Facto law that effectively decriminalizes certain acts or alleviates punishments in a retroactive fashion.

A law may constitute an Ex Post Facto effect without being regarded as a true Ex Post Facto law. For example, when an authority repeals a previous law, the repealed legislation is no longer applied to the situations it once regulated, even if exacting situations arose before the law was altered.

Ex Post Facto Law in the United States:

In the United States of America, the federal government is barred from passing Ex Facto Laws; Clause 3 of Article 1, section 9 of the United States Constitution prohibits the federal government from passing such laws. Individual states are also prohibited from passing Ex Fact Laws as stated in clause 1 of Article 1, section 10 of the United States Constitution. That being said, the presence of Ex Post Facto laws is permitted given the need upon review of the United States Supreme Court.

Although the majority of proposed Ex Post Facto laws have been regarded as unconstitutional, laws with ex post facto effects, such as the Adam Walsh Child Protection and Safety Act of 2006, have been permitted and affirmed by the United States government. This example of an Ex Post Facto law imposed new registration requirements for convicted sex offenders—the new requirements in the Adam Walsh Child Protection and Safety Act were also applied to offenders whose crimes were committed before the law was enacted. The Supreme Court ruled that this law carried an Ex Post Facto characteristic, because the application of such requirements did not constitute any kind of physical punishment.

NEXT: Interaction with Constitutional Law