[Rich Z]

Quite simply, this is an ex post facto law, which is SPECIFICALLY prohibited in the Constitution. Since all states have agreed to support and defend the US Constitution when they became states of the United States of America, these restrictions do apply to them as well.

Ex post facto
Latin for "from a thing done afterward." Ex post facto is most typically used to refer to a law that applies retroactively, thereby criminalizing conduct that was legal when originally performed. Two clauses in the US Constitution prohibit ex post facto laws: Art 1, § 9 and Art. 1 § 10. see, e.g. Collins v. Youngblood 497 US 37 (1990) and California Dep't of Corrections v. Morales 514 US 499 (1995).

EX POST FACTO CLAUSE - A misnomer in that actually two Constitutional clauses are involved. The U.S. Constitution's Article 1 Section 9, C.3 states: 'No Bill of Attainder or ex post facto Law shall be passed,' and Section 10 says: 'No State shall enter into any Treaty, Alliance, or Confederation; grant Letters of Marque and Reprisal; coin Money; emit Bills of Credit; make any Thing but gold and silver Coin a Tender in Payment of Debts; pass any Bill of Attainder, ex post facto Law. . . .'

The 'words and the intent' of the Ex Post Facto Clause encompass '[e]very law that changes the punishment, and inflicts a greater punishment, than the law annexed to the crime, when committed.' Calder v. Bull, 3 U.S. (1 Dall.) 386, 390 (1798) (opinion of Chase, J.).

An ex post facto law is a law passed after the occurrence of an event or action which retrospectively changes the legal consequences of the event or action.

Why are pro-gun attorneys in such short supply?