<P> Some former vice presidents have sought other offices after serving as vice president . Daniel D. Tompkins ran for Governor of New York in 1820 while serving as vice president under James Monroe . He lost to DeWitt Clinton, but was re-elected vice president . John C. Calhoun resigned as vice president to accept election as US Senator from South Carolina . Hannibal Hamlin, Andrew Johnson, Alben Barkley and Hubert H. Humphrey were all elected to the Senate after leaving office . Levi P. Morton, vice president under Benjamin Harrison, was elected Governor of New York after leaving office . </P> <P> Adlai Stevenson I was narrowly defeated for Governor of Illinois in 1908 . Richard Nixon unsuccessfully sought the governorship of California in 1962, nearly two years after leaving office as vice president and just over six years before becoming president . Walter Mondale ran unsuccessfully for president in 1984, served as U.S. Ambassador to Japan from 1993 to 1996, and then sought unsuccessfully to return to the Senate in 2002 . George H.W. Bush won the presidency, and his vice president, Dan Quayle, sought the Republican nomination in 2000 . </P> <P> Since 1977, former presidents and vice presidents who are elected or re-elected to the Senate are entitled to the largely honorific position of Deputy President pro tempore . So far, the only former vice president to have held this title is Hubert Humphrey following his return to the Senate . Walter Mondale would have been entitled to the position had his 2002 Senate bid been successful . </P> <P> Under the terms of an 1886 Senate resolution, all former vice presidents are entitled to a portrait bust in the Senate wing of the United States Capitol, commemorating their service as presidents of the Senate . Dick Cheney is the most recent former vice president to be so honored . </P>

How does the constitution describe the role of the vice president