vice president
the second-highest-ranking official of the U.S. government and first in line to assume the presidency if the president dies, resigns, or becomes unable to serve. Though given only one responsibility in the Constitution—to serve as president of the U.S. Senate, with the power to break ties—the vice presidency has become a visible part of the modern White House. Today’s vice presidents undertake a variety of functions, from serving as an all-purpose presidential advisor to carrying out diplomatic trips abroad. The personality of the individual who occupies this post and their relationship with the president define the scope of the role.