The express powers of the vice president of the United States are to be the presiding officer of the Senate, to act as a ceremonial assistant, to cast the swaying vote if there is a tie in the Senate and to be prepared to take over presidential duties should the president be unable to serve, according to the U.S. Senate page. The vice president is considered to be the second-most important official in the government though the position has often been misunderstood by many.
In fact, more than half of the vice presidents have gone on to serve as president. The first two vice presidents of the U.S. were John Adams and Thomas Jefferson. Both men won election as president immediately after serving as vice president.
The vice president also helps to shape policy and receives advice on many national security matters within the White House. The extent to which a vice president is able to advise the president and play an active role in policy decision-making depends on the relationship between the president and the vice president. The role of the vice president was not defined in many terms within the Constitution, so it continues to change in the modern era as new vice presidents define what it means to hold the role.