Ex Post Facto Law

one that takes effect retroactively; that is, on transactions which took place before its pa age. The provision in the Con: stitution of the United States, Article I, section 9, clause 3, that “ng... ex post facto law shall be pa ed,” has been interpreted to refer only to crimes, and in that sense the words are commonly used. The following have been decided to come within the scope of the phrase: Every law that makes an action done before its pa age, and innocent when done, criminal, and punishes such action; every law that aggravates a crime, or makes it _.. than when committed; every law that changes the nature of the punishment, or makes it greater than at the time the act was committed; every law that alters the rules of evidence so as to make it easier to convict the offender; every law that, while not avowedly relating to. crimes, in effect imposes a penalty or the deprivation of a right; every law that deprives persons accused of crime of some lawful protection to which they have become entitled, as a former acquittal. Such laws are therefore unconstitutional so far as they apply to acts committed before their pa age.