The speech and debate clause, which appears in Article 1, section 6, of the U.S. Constitution, was written before the First Amendment and has a more limited scope.
The clause, whose inclusion reflected the development in England of an independent Parliament, states that “for any Speech or Debate in either House, they [members] shall not be questioned in any other Place.” It follows a provision, now largely moot, that prevents the arrest, for civil cases, of members traveling to or from sessions of Congress.