What is Congress?

Overview of Congressional Structure & Leadership

“All legislative Powers herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and a House of Representatives.” 
—Article I, Section I, U.S. Constitution

Congress is the governing legislature of the U.S. comprised of two chambers: the Senate and House of Representatives. The Senate is composed of 100 members, two from each state, who are elected to serve for a term of six years. Senators were originally chosen by the state legislatures. This procedure was changed by the 17th Amendment to the Constitution, adopted in 1913, which made the selection of senators a decision for the people. There are three classes of senators. A new class is elected every two years.

The House of Representatives is composed of 435 members. The number representing each state is determined by population, but every state is entitled to at least one representative. Members are elected by their constituents for two year terms, all terms running for the same period. Both the senators and the representatives must be residents of the state from which they are chosen. In addition a senator must be at least 30 years of age and must have been a citizen of the United States for at least nine years. A representative must be at least 25 years of age and must have been a citizen for at least seven years.


The Vice President of the United States is the “presiding officer” of the Senate; in his absence the duties are performed by the president pro tempore. The presiding officer of the House of Representatives is the “speaker” who is elected by the House members. The Speaker may designate any member of the House to act in his/her absence.

The positions of Senate “majority and minority leaders” have been in existence only since the early years of the twentieth century. These leaders are elected at the beginning of each new Congress by a majority vote of the senators in their political party. In cooperation with their party organizations, leaders are responsible for the design and achievement of a legislative program. This involves managing the flow of legislation, expediting non-controversial measures, and keeping members informed regarding proposed action on pending business. Each leader serves as an ex officio member of his party’s policymaking and organizational bodies, and is aided by an assistant floor leader, or whip, and a party secretary.

The House leadership is structured essentially the same as the Senate, with the members each political party responsible for the election of their respective leader and whips. For a directory of the current members of Congress, their committee assignments, and leadership roles, click here