This document discusses and compares the U.S. and Indian positions on ex post facto laws. In the U.S., Calder v. Bull established four categories of ex post facto laws: 1) making innocent acts criminal; 2) aggravating crimes; 3) increasing punishments; 4) altering evidentiary rules to convict. Dobbert v. Florida held that procedural changes are allowed if generally ameliorative. In India, Union of India v. Super Processors established that changed penalties are allowed if the maximum is unchanged.