Lautenberg and ex post facto
Over at Gun Law News there's a debate on whether the Lautenberg amendment (making persons convicted of misdemeanor domestic violence into persons prohibited to possess guns) violates the ban on ex post facto laws.
I think GLN has it right. Lautenberg doesn't violate one arm of ex post facto (you can't criminalize conduct retroactively -- Lautenberg passes muster because to violate it a person must possess a gun after it was enacted) but does violate the other arm, at least for DV offenses commited before Lautenberg was passed (you can't increase punishment, in this case for the DV offense, after the offense was committed).
Not that any court's going to buy the theory. As I recall, they either ignore it, brush it off, or reason by analogy that putting conditions on something like permit or licensing isn't punishment. It might be interesting to bring a case in the Fifth Circuit, tho, since that circuit has recognized that the Second Amendment is an individual right. It's hard to apply reasoning keyed to permitting (government has no duty to license a person, it merely grants a privilege) to a restriction, indeed a complete cutoff, of a constitutional right.