After Senator Mike Gravel read portions of the Pentagon Papers into a subcommittee record and arranged their private publication, a grand jury sought to question his aide. Justice White's opinion held that the Speech or Debate Clause of Article I, § 6 shields members and their aides from being 'questioned in any other place' about legislative acts — but it does not extend to Gravel's arrangement with a private publisher, which was not part of the legislative function. Gravel is the leading modern authority on the reach of legislative immunity and on what counts as a protected 'legislative act.'