President pro tempore of the United States Senate= President pro tempore (/ˌproʊ ˈtɛmpəriː/ or /ˌproʊ ˈtɛmpəreɪ/), also president pro tem, is the second-highest-ranking official of the United States Senate. The United States Constitution states that the Vice President of the United States is the President of the Senate, despite not being a senator, and that the Senate must choose a president pr...