The sergeant at arms and doorkeeper of the United States Senate is the protocol officer, executive officer, and highest-ranking federal law enforcement officer of the Senate of the United States. The office of the sergeant at arms of the Senate currently has just short of 1,000 full time staff.

The United States Senate is the upper chamber of the United States Congress. The United States Senate and the lower chamber of Congress, the United States House of Representatives, comprise the federal bicameral legislature of the United States. Together, the Senate and the House maintain authority under Article One of the U.S. Constitution to pass or defeat federal legislation. The Senate has exclusive power to confirm U.S. presidential appointments, approve or reject treaties, and try cases of impeachment brought by the House. The Senate and the House provide a check and balance on the powers of the executive and judicial branches of government.