Should repeal of a law void previous convictions?
Scenario: A guy is convicted and sentenced to 50 years in prison for wearing plaid shorts in public in 1997. Fast forward to 2004, and the law against wearing plaid shorts in public is repealed. The guy is 7 years into his 50 year sentence. But... his wearing of plaid shorts in public is no longer deemed a crime.
Should he be released, or should he serve the remainder of his sentence?
Conceptual question purposely made up so we don't get sidetracked regarding specific real crimes.
I don't think there's an easy, once-size-fits-all yes/no answer to this.
The Constitution prohibits the enactment of an “ex post facto law”. What this means, is that a law cannot be enacted that takes effect before the time it is actually enacted. The best practical example would be passing a law which criminalizes a particular behavior, then prosecuting someone for engaging in that behavior before the law actually took effect. Say the law is enacted and takes effect in 1997, and the guy in the OP's example is convicted based on evidence that he was seen in public wearing plaid shorts in 1996. You cannot legally someone for doing something that was legal at the time that he did it.
I think a case could be argued that the ex post facto principle applies the other way as well; that someone who did something that was illegal at the time he did it is still culpable for that crime even if the act that he committed has since been legalized.
Given that the Constitution as a whole is intended as a restraint on government, and where it covers criminal matters in particular, the Constitution and the body of “common law”*on which it is founded supports a balance much more in favor of one who is accused of a crime than on government to prosecute someone for a crime (hence such things as the “innocent until proven guilty” principle, the requirement for a unanimous jury verdict to convict, and the non-appealability of an “innocent”*verdict); I see plenty of room to limit the use of the ex post facto principle as far as retaining a conviction for an act that ls later legalized.
Perhaps it should be valid for a law which legalizes a previously illegal act to include a provision that explicitly states that any previous convictions for the act being legalized are overturned, and once such a law takes effect, any who have ever been convicted for the now-legalized act would automatically have their conviction removed from the record, and any who are still serving sentences would immediately be released from the remainder thereof. I suppose we'd need the courts to determine whether such a provision can actually be valid, or whether it would still violate the ex post facto principle.
I suppose a away around the ex post facto principle might be for every such bill to include some sort of mass-pardon provision, so that when the President/Governor/Mayor is signing that bill into law, he is also signing a pardon for any convictions that were based on the now-legalized behavior.
As a matter of ethics, I can see it possible to go either way.
I can imagine there being situations where it is harmful at one time to engage in a particular behavior, to the degree that it is reasonable to enact laws against that behavior and to prosecute as criminals those who engage in it; and the situation to later change so that the same behavior is no longer harmful, and it is no longer reasonable to prosecute people as criminals for doing it; but where it is still reasonable for those who were convicted of that behavior when it was illegal to continue to be treated as criminals.
I can also imagine situations where a populace might simply decide that a behavior that was once regarded as harmful never really was, and that not only should people no longer be prosecuted for it, but that those who previously were convicted should no longer bear the stain of that conviction.
