Ex post facto only applies to criminal laws (Calder v. Bull). And it generally only applies to punishments for crimes. See how sex offenders had to register e

Ex post facto only applies to criminal laws (Calder v. Bull). And it generally only applies to punishments for crimes. See how sex offenders had to register even if their crimes were committed before the Adam Walsh bill was passed, because registering as a sex offender is not a punishment.