The constitution of the United States, art. 2, s. 4, provides, that the president, vice-president, and civil officers of the United States, shall be removed from office on impeachment for, and conviction of treason, bribery, or other high crimes and misdemeanors. By this term are included all officers of the United States who hold their appointments under the national government, whether their duties are executive or judicial, in the highest or the lowest departments; of the government, with the exception of officers of the army and navy. Rawle on the Const. 213; 2 Story, Const. 790; a senator of the United States, it was decided, was not a civil officer, within the meaning of this clause in the constitution.