United States Senate

The United States Senate is the upper house of the bicameral United States Congress, the lower house being the House of Representatives.
In the Senate, each state is represented by two members, in accordance with the New Jersey Plan, proposed by William Paterson reached at the Philadelphia Convention of 1787. The Senate's membership is therefore based on the equal representation of each state, regardless of population.
Since there are now 50 states, the total membership of the body is 100. Senators serve for six-year terms that are staggered so elections are held for a third of the seats (a "class") every second year (rounded out, so that one class has thirty-four Senators). The Vice President of the United States is the President of the Senate and serves as its presiding officer, but is not a senator and does not vote except to break ties. The Vice President rarely acts as President of the Senate unless casting a tie-breaking vote or during ceremonial occasions. As such, the duty of presiding usually falls to the President pro tempore, by tradition the most senior senator of the majority party, who almost always delegates the routine task of presiding over the Senate to junior senators from that party.
The Senate is regarded as a more deliberative body than the House of Representatives; the Senate is smaller and its members serve longer terms, allowing for a more collegial and less partisan atmosphere that is somewhat more insulated from public opinion than the House. The Senate has several exclusive powers enumerated in Article One of the Constitution not granted to the House; most significantly, the President cannot ratify treaties or, with rare exception, make important appointments—most significantly ambassadors, members of the federal judiciary (including the Supreme Court) and members of the Cabinet—without the advice and consent of the Senate.