Twenty-second Amendment to the United States Constitution
Some argue that the 22nd Amendment and 12th Amendment bar any two-term president from later serving as vice president as well as from succeeding to the presidency from any point in the presidential line of succession. Others contend that the original intent of the 12th Amendment concerns qualification for "service" (age, residence, and citizenship), while the 22nd Amendment, concerns qualifications for "election", and thus (strictly applying the text) a former two-term president is still eligible to "serve" as vice president (neither amendment restricts the number of times an individual can be elected to the vice presidency), and then succeed to the presidency to serve out the balance of the term (though prohibited from running for election to an additional term).
Vice President of the United States
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. To date, the only former vice president to have held this title is Hubert Humphrey following his return to the Senate. Also, 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.