Which term describes a law that makes an act a crime after the act was committed?

• A. Ex post facto law
• B. Habeas corpus
• C. Independent judiciary
• D. Public interest

Answer: (A)

A law that makes an act a crime after it was committed is called an ex post facto law. This concept describes punishing someone for an action that was legal at the time they did it, or increasing the punishment after the fact. The idea protects fairness and predictability, since people should be judged by the rules that existed when they acted. An example would be passing a new law tomorrow that punishes yesterday’s conduct; applying it retroactively would be ex post facto.

Habeas corpus is about challenging unlawful detention, ensuring a person isn’t held without justification. An independent judiciary refers to having courts that operate free from political influence. Public interest concerns the welfare of the community in lawmaking. None of these describe retroactive criminalization, which is why ex post facto law is the correct term.