What does a bill of attainder do?

A bill of attainder is a legislative act that declares a specific individual or group guilty of a particular crime and imposes punishment without the benefit of a trial. This practice is considered a violation of the principle of due process, as it denies the affected parties the opportunity for a fair hearing and legal defense. The U.S. Constitution explicitly prohibits bills of attainder in Article I, Section 9, ensuring that individuals cannot be stripped of their rights and punished without the legal protections afforded by a trial. This prevents the misuse of legislative power to target individuals or groups for punishment based solely on the decisions of lawmakers, highlighting the importance of judicial proceedings and fair trial rights in a democratic society.