What is a bill of attainder?
A bill of attainder is a law that punishes a named person or group without a trial.
Congress.gov is the source of record for this guide. The Constitution Annotated history of bills of attainder explains the definition and its roots in English law.
Why does the Constitution ban bills of attainder?
Article I, Section 9 bars Congress from passing a bill of attainder. Article I, Section 10 bars the states from passing one.
The ban keeps lawmakers from acting as judges who punish specific people without a trial. It protects the separation of powers and the right to a judicial process.
Does every law that names someone violate the ban?
No. A law must impose punishment, not merely affect a specific person or group. Courts consider whether a law serves a nonpunitive purpose, not just whether it places a burden on someone.
The Constitution Annotated guide to bills of attainder doctrine explains how courts apply the ban. The protection covers punishment beyond the death penalty, including some restrictions on employment.
How does the ban limit Congress?
The Constitution both grants powers and sets limits. Congress can use its listed powers to make laws, but it cannot bypass the ban on bills of attainder.
The enumerated powers guide explains the powers the Constitution grants. The Congress guide explains how the House and Senate share lawmaking power.
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