A majority leader is the leader of a parliamentary group or party which constitutes a majority or plurality within a legislature in political systems where the legislature does not form the executive branch. They are commonly found in the legislatures of states which use a single-executive system of government.
In U.S. politics (as well as in some other countries utilizing the presidential system), the majority floor leader is a partisan position in a legislative body.
United States
In the federal Congress of the United States, the roles of the House majority leader and the Senate majority leader differ slightly. At the state level, the majority leader of a given state legislative chamber usually performs a similar role to that of their federal counterpart.
Senate
In the Senate, the vice president of the United States is officially the president of the Senate and the president pro tempore serves as the president of the Senate in the absence of the vice president. However, in reality, the vice president seldom enters the Senate, let alone directly presides over the chamber, unless a tied vote is expected, and the president pro tempore has become a ceremonial role deprived of any leadership ability.
Thus, the majority leader is seen as the de facto leader of the Senate, especially in modern times, and thus, in accordance with Senate rules, the presiding officer of the day gives the majority leader priority in obtaining recognition to speak on the floor of the Senate and they determine which bills get voted on. The majority leader is seen as the chief spokesperson for their party in the Senate.