The United States Congress is the legislature of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washington, D.C. Senators and representatives are chosen through direct election, though vacancies in the Senate may be filled by a governor's appointment. Congress has 535 voting members: 100 senators and 435 representatives. The U.S. vice president has a vote in the Senate only when senators are evenly divided. The House of Representatives has six non-voting members.

The vice president of the United States (VPOTUS) is the second-highest officer in the executive branch of the U.S. federal government, after the president of the United States, and ranks first in the presidential line of succession. The vice president is also an officer in the legislative branch, as the president of the Senate. In this capacity, the vice president is empowered to preside over the United States Senate, but may not vote except to cast a tie-breaking vote. The vice president is indirectly elected together with the president to a four-year term of office by the people of the United States through the Electoral College. Since the passage of the Twenty-fifth Amendment to the US Constitution, the vice president may also be appointed by the president to fill a vacancy, via majority confirmation by both the Senate and the House.