The most influential members of Congress include the Speaker of the House and the majority and minority leaders in both the House of Representatives and the Senate. Additionally, the heads of important committees, such as the Ways and Means Committee, wield significant influence on the creation and funding of laws. Most of these positions change hands with moderate frequency, particularly when a new party takes a majority in either the House or Senate after an election.
The majority leader, which refers to the head of the party with a majority of seats in either the House or Senate, holds influence over which congressperson heads various committees. The Speaker of the House influences the creation of laws with the power to call legislation for a vote. Generally, these roles fall to representatives and senators who have served multiple terms in office. Likewise, the role of chairperson for the most influential committees usually falls to long-serving members of Congress in the majority party. As of 2015, the Senate features 20 committees and more than 60 subcommittees. The House includes 21 committees, and four committees include members of both the Senate and the House. Each committee creates its own rules and guidelines to operate by, providing the chairs varying degrees of influence in addition to the importance of the committee content.