Assuming this is about the united states, to pass an ex post facto law is no kind of power, it is prohibited by the constitution.
No. Article I, Section 9, paragraph 3 of the Constitution prohibits Congress from passing ex post facto laws.
ex post facto laws and Bills of Attainder
Ex post facto laws are specifically prohibited by the Constitution.
false
The legal term for a law that has criminal penalties that effect people prior to the enactment of that law is called an "ex-post facto law". Ex-post facto laws are illegal in most countries and the US Constitution expressly forbids the creation or passage of an ex-post facto law.
Ex post facto :)
passing ex post facto laws
Ex Post Facto Laws (after the fact)
Ex post facto laws are laws that act retrospectively. The law changes the legal consequence of an action that was committed before the enactment of the law. For example, an action that was not criminal in 1990 may be regarded as a crime if new legislation is passed to ban the action.
(in the US) Ex Post Facto laws are forbidden by the US Constitution.
none. Section 22. No ex post facto law or bill of attainder shall be enacted.