Ex Post Facto
Definition
With retroactive effect or force.
Deep Dive
An ex post facto law is a law that retroactively changes the legal consequences (or status) of actions that were committed before the enactment of the law. In criminal law, this typically means a law that makes an act criminal that was legal when it was committed, increases the punishment for a crime after it was committed, or alters the rules of evidence to make conviction easier for past crimes. The principle against ex post facto laws is a fundamental safeguard in many legal systems, including the United States Constitution, designed to protect individuals from arbitrary legislative power and ensure predictability and fairness in the law. This prohibition ensures that citizens can rely on the current laws when making decisions, without fear of being retroactively penalized for actions that were lawful at the time they occurred.
Examples & Use Cases
- 1A state passes a law making it a crime to share certain digital content, then attempts to prosecute individuals who shared that content before the law was enacted
- 2A legislature increases the maximum prison sentence for a specific type of fraud and attempts to apply the new, harsher sentence to someone convicted of that fraud prior to the law change.