The number of representatives allotted to each state is based on its population as determined by a decennial census. The overall membership of the House has been 435 since the 1910s, though it was temporarily expanded to 437 after Hawaii and Alaska were admitted as states in 1959. Members must be 25 years old, residents of the states from which they are elected, and previously citizens of the United States for at least seven years. It has become a practical imperative "though not a constitutional requirement "that a member be an inhabitant of the district that elects him. Members serve two-year terms. The speaker of the House, who is chosen by the majority party, presides over debate, appoints members of select and conference committees, and performs other important duties. The parliamentary leaders of the two parties are the majority floor leader and the minority floor leader. The floor leaders are assisted by party whips, who are responsible for maintaining contact between the leadership and the members of the House. Bills introduced by members in the House of Representatives are received by standing committees, which can amend, expedite, delay, or kill legislation. Each committee is chaired by a member of the majority party, who traditionally attained this position on the basis of seniority, though this practice has come under increasing challenge since the 1970s. Among the most important committees are those on Appropriations, Ways and Means, and Rules. The Rules Committee, for example, has significant power to determine which bills will be brought to the floor of the House for consideration and whether amendments will be allowed on a bill when it is debated by the entire House.
Each state elects two senators at large. Senators must be at least 30 years old, residents of the state from which they are elected, and previously citizens of the United States for at least nine years.
