Structure of the U.S. House and Senate

The Constitution says very little about the actual organization of the House of Representatives and Senate. Article 1, Section 2, stipulates that members of the House should choose "their speaker and other officers." The Speaker of the House is the presiding officer and powerful leader of the House of Representatives and is second in the line of presidential succession after the vice president. Although the Constitution does not require the Speaker be a member of the House of Representatives, all Speakers have been members. Speakers are elected by House members at the beginning of a session of Congress; unsurprisingly, the elected representative is always a member of the majority party. When he or she is present, the Speaker presides over the House; when absent, another House member is designated as the presiding officer. No representative may speak on the floor of the House until recognized by the person presiding over the chamber. Speakers generally do not make floor speeches or vote on legislation.

Under the Speaker of the House, there are a majority leader and a minority leader. The majority leader represents the majority party's policy positions in the House of Representatives or Senate. The leader of the opposition party is called the minority leader, who represents the minority party's policy positions in the House of Representatives or Senate. These party leaders are typically well known and vocal about the legislation making its way through Congress. They often meet with the president to discuss issues and possible compromises.

A majority whip and a minority whip both serve as floor leaders for their respective parties. A whip is a member of the House of Representatives or Senate chosen by the party's caucus who encourages votes and loyalty from members of the majority or minority party. The whips assist their party's congressional leadership by working closely with the other members of the party. In practice, party discipline has generally been more noticeable in the House than the Senate.

There are a few other powerful positions within the House, including membership on the Rules Committee. Because members of this committee are responsible for deciding which bills will be debated on the floor—as well as for how long and what parameters there are for amending legislation—it is considered one of the most powerful committees in the House.

Most of the House's 435 members do not have direct leadership roles. Instead, they work on sponsoring legislation that will benefit their constituents back home and regularly attend meetings with staff, fellow representatives, members of the press, and interest groups. Fundraising is also a major concern for House members, who typically seek reelection at the end of their two-year term. Leaders and select members work on fundraising for their party's congressional campaign committee.

Given the greater number of House members, they often specialize in a certain area, such as energy policy or foreign affairs. The work they do on these committees influences the reputation they build for themselves in Washington, D.C., and back home in their districts.

Article 1, Section 3, of the U.S. Constitution assigns the position of president of the Senate to the vice president of the United States, but this job is typically filled by the president pro tempore, a senator who acts as a temporary president. The president pro tempore is elected by the majority party and presides over the Senate in the absence of the vice president, interpreting and applying Senate rules and recognizing members to speak during debates.

As in the House, a majority and minority leader oversee the operation of the Senate. The majority leader is the unofficial spokesperson of the Senate and schedules debate on the floor, working with the minority leader on actual debate time allotments. The majority leader also has the right of first recognition on the Senate floor, meaning that he or she is called on first to propose amendments and other procedural motions before any other senator. The minority leader has second right. There are also majority and minority whips in the Senate, who work to ensure party discipline and fulfill the leader's role on the floor of the Senate in the leader's absence.

Members of Congress also join together in various bodies called caucuses, which formed over time and are not required by the Constitution. Each party has two caucuses in Congress, with one formed of members from each chamber. (Republicans call these groups the House and Senate Conference; Democrats use the term caucus.) Members meet from time to time to try to reach policy agreement within the party's congressional delegation on particular issues. At the beginning of a session of Congress, or whenever leadership positions open, the members choose the party's leaders for the chamber.

Members with shared interests, whether that be a particular ideological position, interest in a certain issue or issues, or interest in the concerns of an ethnic group, also form focused caucuses. Technically called congressional member organizations (CMOs), these groups have members who try to work together to promote their policy goals. Because political parties tend to include a range of views, a given party may be home to conflicting ideological caucuses. For instance, House Republicans have included both the Tuesday Group, with moderate members, and the House Freedom Caucus, with members linked to the very conservative Tea Party movement. The Congressional Black Caucus, founded in 1971, includes African American members of Congress from both parties and from both chambers.