The Privilege from Arrest Clause, found in Article I, Section 6 of the U.S. Constitution, protects members of the U.S. legislature from being arrested "in all Cases, except Treason, Felony and Breach of the Peace" while Congress is in session. The clause also protects members of Congress from arrest on their way to or from sessions of Congress.

Cause of the Clause

At the time the Constitution was written, it was not uncommon for people to be arrested for civil matters. The Protection from Arrest Clause was put into the Constitution to ensure that rival political factions could not use trivial legal matters to hinder members of Congress from participating in the legislative process. Members of Congress can still be arrested on criminal charges at any time.