The Senate is composed of senators, each of whom represents a single state in its entirety. The presiding officer of the Senate is the vice president of the United States, who is president of the Senate. In the vice president's absence, the president pro tempore, who is customarily the senior member of the party holding a majority of seats, presides over the Senate. The Senate was thus not designed to serve the people of the United States equally. First convened in 1789, the Senate of the United States was formed on the example of the ancient Roman Senate. The United States has had 50 states since 1959, thus the Senate has had 100 senators since 1959.
The party composition of the Senate during the 116th Congress:
The Senate (not the judiciary) is the sole judge of a senator's qualifications. As a result, three senators who failed to meet the age requirement were nevertheless admitted to the Senate: Senators are elected by their state as a whole. The Seventeenth Amendment requires that mid-term vacancies in the Senate be filled by special election. Nine states – According to the convention of Senate seniority, the senator with the longer tenure in each state is known as the "senior senator"; the other is the "junior senator". The Senate may expel a senator by a two-thirds vote. The Senate has also censured and condemned senators; censure requires only a simple majority and does not remove a senator from office. At one end of the chamber of the Senate is a dais from which the presiding officer presides. Each senator chooses a desk based on seniority within the party. Except for the president of the Senate, the Senate elects its own officers, who maintain order and decorum, manage and schedule the legislative and executive business of the Senate, and interpret the Senate's rules, practices and precedents. Under the Constitution, the vice president serves as president of the Senate. Since the 1950s, vice presidents have presided over few Senate debates. Like the vice president, the president pro tempore does not normally preside over the Senate, but typically delegates the responsibility of presiding to a majority-party senator who presides over the Senate, usually in blocks of one hour on a rotating basis. The presiding officer sits in a chair in the front of the Senate chamber. The presiding officer calls on senators to speak (by the rules of the Senate, Each party elects Senate party leaders. The Senate majority leader is responsible for controlling the agenda of the chamber by scheduling debates and votes. In addition to the vice president, the Senate has several officers who are not members. The assistant secretary of the Senate aids the secretary's work. Another official is the sergeant at arms who, as the Senate's chief law enforcement officer, maintains order and security on the Senate premises. The Senate uses Standing Rules for operation. Like the House of Representatives, the Senate meets in the United States Capitol in Washington, D.C. At one end of the chamber of the Senate is a dais from which the presiding officer presides. The Senate commonly waives some of its stricter rules by unanimous consent. The presiding officer enforces the rules of the Senate, and may warn members who deviate from them. The presiding officer sometimes uses the gavel of the Senate to maintain order. The Constitution provides that a majority of the Senate constitutes a quorum to do business. Debate, like most other matters governing the internal functioning of the Senate, is governed by internal rules adopted by the Senate. Senators address the Senate standing next to their desk. The rules of the Senate provide that no senator may make more than two speeches on a motion or bill on the same legislative day. Often, the Senate adopts unanimous consent agreements imposing time limits. The Senate may end a filibuster by invoking cloture. The Senate often votes by voice vote. The Senate maintains a Senate Calendar and an Executive Calendar. The former identifies bills and resolutions awaiting Senate floor actions. The latter identifies executive resolutions, treaties, and nominations reported out by Senate committee(s) and awaiting Senate floor action. the Senate is in session.
Formally, the whole Senate appoints committee members. Committees may block nominees and impede bills from reaching the floor of the Senate. The Senate also has several committees that are not considered standing committees. The Congress includes joint committees, which include members from both the Senate and the House of Representatives. Each Senate committee and subcommittee is led by a chair (usually a member of the majority party). They are the Russell Senate Office Building, the Dirksen Senate Office Building, and the Hart Senate Office Building.
Historically, the Senate has disputed the interpretation advocated by the House. The president can make certain appointments only with the advice and consent of the Senate. Typically, a nominee is first subject to a hearing before a Senate committee. Thereafter, the nomination is considered by the full Senate. The Senate also has a role in ratifying treaties. Congress has passed laws authorizing the president to conclude executive agreements without action by the Senate. Conviction requires a two-thirds majority of the senators present. (One resigned before the Senate could complete the trial.)
Summary of this Wikipedia page.