ex post facto law

Cultural  

1. A law that makes illegal an act that was legal when committed, increases the penalties for an infraction after it has been committed, or changes the rules of evidence to make conviction easier. The Constitution prohibits the making of ex post facto law. (See ex post facto (see also ex post facto).)

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Example Sentences

Because genocide became an official crime only after the Nuremberg trials, Germany decided in 1949 that charging former Nazis with this crime would amount to ex post facto law.

From Washington Post

“If the Supreme Court attempts to apply the decision to the people who have already gotten new sentencing hearings, or who are now awaiting new sentencing hearings, there’s a very strong argument that it’s an ex post facto law and it’s unconstitutional,” he said, referring to a law that applies to crimes which happened before the law was passed.

From Seattle Times

The trial court denied that claim, but the state Supreme Court overturned the lower court, ruling that the repeal was an invalid ex post facto law that also denied Keith of the due process he was owed under the original act.

From Slate

Constitution bars convicting someone under an ex post facto law, meaning one adopted after the alleged crime.

From Reuters

“If Trump issues pardons while this gap in the law remains, then a later fix to the statute might be deemed an ‘ex post facto’ law that could not apply to the individuals already pardoned.”

From Salon