yes
This is called an ex post facto law. They are constitutionally illegal in the United States. Ex post facto is Latin for from after the action or after the facts.
Yes, an ex post facto law cannot impose punishment on a person who committed an act before it was illegal. This includes increasing the severity of the punishment from what it was when the crime was committed. Ex post facto applies to criminal law and not civil law as interpreted by the U.S. Supreme Court. Also, some laws, for example the sex offenders registry, are considered a regulatory device for public safety and not a punitive action. no ex-post facto law after the fact. no ex-post facto law after the fact.
Ex Post Facto protects a person from being charged with breaking the law or committing a crime if they committed it before the law went into effect. For example if I committed a crime but at the time it wasn't against the law but they soon passed a law saying that it was illegal they could not come after me for having committed a crime that at that time would not have been a crime.
In the United States, Congress is forbidden of passing what is known as "Ex Post Facto Laws." The United States Supreme Court uses the case of Calder v. Bull in which they ruled that prohibition applied only to criminal, not civil cases to decide ex post facto challenges.
Ex post facto :)
"Ex Post Facto relates to a change in the law (or the penalties for violation of a law) after a crime has been committed. In most cases, criminal law does not take into consideration what is basically a retroactive change in the law in effect at the time a crime was committed."
If you haven't committed any illegal acts there is nothing to charge you with.
That is known as an Ex post facto law. It is Latin for "after the fact." Article I, sections 9 and 10 of the Constitution prevent states and the national government (congress) from enacting such laws.
An ex post facto law is one that is made retroactive to punish an act that wasn't illegal at the time it was committed. For example, if I didn't wear my seatbelt and wearing one wasn't a law, but it became a law the next day, I couldn't get in trouble for it because the "crime" was committed before it was against the law. Article I of the US Constitution specifically says this cannot be done. Laws that don't involve penalties can reference dates in the past to allow an income tax break or permit eligibility for a program based on past actions (such as fighting in a war). The reason the Constitution prevents Congress (and the states) from writing ex post facto laws is to protect the population and other entities from government abuse.
An "ex post facto" law. In theory, our Constitution forbids this. In practice, there are several notable examples of it having been done and upheld by our courts.
They cannot pass a law that goes into effect retroactively. This means that they can't make something that was done prior to their passing the law illegal. It prevents them from making people that did something they didn't like a criminal for something done months or even years earlier.
Retrospective law, also known as ex post facto law, punishes individuals for actions that were legal when committed but are later made illegal. This type of law is generally prohibited by many legal systems because it violates fundamental principles of fairness and justice.