<P> As President of the Senate (Article I, Section 3, Clause 4), the vice president has two primary duties: to cast a vote in the event of a Senate deadlock and to preside over and certify the official vote count of the Electoral College . For example, in the first half of 2001, the Senators were divided 50 - 50 between Republicans and Democrats . The Democrats had the majority from January 3 to noon January 20 with Al Gore's tie - breaking vote . Dick Cheney's tie - breaking vote gave the Republicans the Senate majority until June 6, 2001 when Jim Jeffords left the Republican Party . </P> <P> The vice president oversees procedural matters in the Senate, and may cast a tie - breaking vote . There is a strong convention within the Senate that the vice president should not use his position as President of the Senate to influence the passage of legislation or act in a partisan manner, except in the case of breaking tie votes . As of February 2, 2018, a total of 262 tie - breaking votes had been cast by 36 vice presidents . As President of the Senate, John Adams cast 29 tie - breaking votes, a number later surpassed by John C. Calhoun with 31; no other vice president since then has ever threatened this record . Adams's votes protected the president's sole authority over the removal of appointees, influenced the location of the national capital, and prevented war with Great Britain . On at least one occasion Adams persuaded senators to vote against legislation he opposed, and he frequently addressed the Senate on procedural and policy matters . Adams's political views and his active role in the Senate made him a natural target for critics of George Washington's administration . Toward the end of his first term, a threatened resolution that would have silenced him except for procedural and policy matters caused him to exercise more restraint in hopes of seeing his election as President of the United States . </P> <P> Formerly, the vice president would preside regularly over Senate proceedings, but in modern times, the vice president rarely presides over day - to - day matters in the Senate; in their place, the Senate chooses a President pro tempore (or "president for a time") to preside in the vice president's absence; the Senate normally selects the longest - serving senator in the majority party . The President pro tempore has the power to appoint any other senator to preside, and in practice junior senators from the majority party are assigned the task of presiding over the Senate at most times . </P> <P> Except for this tie - breaking role, the Standing Rules of the Senate vest no significant responsibilities in the vice president . Rule XIX, which governs debate, does not authorize the vice president to participate in debate, and grants only to members of the Senate (and, upon appropriate notice, former presidents of the United States) the privilege of addressing the Senate, without granting a similar privilege to the sitting vice president . Thus, as Time magazine wrote during the controversial tenure of Vice President Charles G. Dawes, "once in four years the Vice President can make a little speech, and then he is done . For four years he then has to sit in the seat of the silent, attending to speeches ponderous or otherwise, of deliberation or humor ." </P>

Who is the leader of the senate when the vp isn't there