“No Bill of Attainder or ex post facto Law shall be passed.” Art. I, Section IX, U.S. Constitution.
A bill of attainder (also known as an act of attainder or writ of attainder or bill of penalties) is an act of a legislature declaring a person, or a group of persons, guilty of some crime, and punishing them, often without a trial.
An ex post facto law (corrupted from Latin: ex postfacto, lit. 'out of the aftermath') is a law that retroactively changes the legal consequences (or status) of actions that were committed, or relationships that existed, before the enactment of the law.
So the question you've got to ask yourself is, "Are these people Constitutionally retarded"? The answer is "Yes".
Well, the Lautenberg Amendment was proof that that ex post facto thingy can be ignored.