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).
2008 United States presidential election
Incumbent Republican President George W. Bush was ineligible to pursue a third term due to the term limits established by the 22nd Amendment. As neither Bush nor Vice President Dick Cheney sought the presidency, the 2008 election was the first election since 1952 in which neither major party's presidential nominee was the incumbent president or the incumbent vice president. McCain secured the Republican nomination by March 2008, defeating Mitt Romney, Mike Huckabee, and other challengers. The Democratic primaries were marked by a sharp contest between Obama and the initial front-runner, Senator Hillary Clinton. Clinton's victory in the New Hampshire primary made her the first woman to win a major party's presidential primary. After a long primary season, Obama clinched the Democratic nomination in June 2008.