From January 3 to June 3, 2008, voters of the Republican Party chose their nominee for president in the 2008 United States presidential election. Senator John McCain of Arizona was selected as the nominee through a series of primary elections and caucuses culminating in the 2008 Republican National Convention held from Monday, September 1, through Thursday, September 4, 2008, in Saint Paul, Minnesota. President George W. Bush was ineligible to be elected to a third term due to the term limits established by the 22nd Amendment.

The 2008 United States presidential election was the 56th quadrennial presidential election, held on November 4, 2008. The Democratic ticket of Barack Obama, the junior senator from Illinois, and Joe Biden, the senior senator from Delaware, defeated the Republican ticket of John McCain, the senior senator from Arizona, and Sarah Palin, the governor of Alaska. Obama became the first African American to be elected to the presidency, as well as being only the third sitting United States senator elected president, joining Warren G. Harding and John F. Kennedy. Meanwhile, this was only the second successful all-senator ticket since the 1960 election and is the only election where both major party nominees were sitting senators. This was the first election since 1952 in which neither the incumbent president nor vice president was on the ballot, as well as the first election since 1928 in which neither ran for the nomination.