A bill of attainder is a piece of legislation that declares a party is guilty of a crime. Bills of attainder allow the government to punish a party for a perceived crime without first going through the trial process.
In the United States, bills of attainder are unconstitutional as stated in Article 1 Section 9 and Article 1 Section 10 of the U.S. Constitution. Article 9 prohibits federal bills of attainder and Article 10 prohibits bills of attainder by the states. The constitutional ban on bills of attainder works to uphold separation of powers principles by preventing Congress from assuming the functions of the judicial branch.
Courts have adopted a three-part test to determine if a law functions as a bill of attainder:
In Nixon v. Adm'r of General Services, the court determined that punishment for the purposes of bills of attainder will determined by considering:
[Last updated in July of 2022 by the Wex Definitions Team]
When a legislative act declares a particular person guilty of a crime (usually treason), such bills are prohibited under Article I, Section 9 of the Constitution.