2008 United States presidential election in Tennessee

• 2008 Tennessee Democratic primary
• 2008 Tennessee Republican primary

Despite narrowly voting for Bill Clinton in 1992 and 1996 when former Tennessee Senator Al Gore was on the ticket as Vice President, the state, along with neighboring Arkansas has steadily been trending Republican since then. George W. Bush narrowly carried the state in 2000 over Gore and easily won in 2004 over John Kerry.

A handful of Tennessean counties—including those that hadn't voted Republican since landslide victors Reagan or Nixon were on the ballot, swung dramatically Republican. For example, Grundy County, in southeastern Tennessee, broke 56%-42% for John Kerry in 2004, but wound up being swept by McCain 55%-42% this year. The state was one of five states that swung even more Republican in 2008 with John McCain soundly defeating Barack Obama in the Volunteer State. 2008 marked the first time since 1960 whereby the state was carried by the losing presidential candidate. A possible factor to Tennessee ironically swinging rightward—despite the national Democratic trend—could be the state favoring Hillary Clinton, former First Lady of neighboring Arkansas, over Barack Obama in the Democratic primary, as was the case in Arkansas itself.

McCain won both East Tennessee and Middle Tennessee by landslide margins. Historically, East Tennessee, which is a part of Appalachia, is one of the few ancestrally Republican areas of the South. Most of its residents strongly opposed secession during the Civil War. They identified with the GOP after the return of peace and have remained in the Republican fold through good times and bad ever since. Some of the region's counties are among the few in the country to have never supported a Democrat for president.

However, Middle Tennessee has Democratic roots based on liberal economic policies, most famously Franklin D. Roosevelt's Tennessee Valley Authority. Middle Tennessee voted strongly for Bill Clinton of neighboring Arkansas, but Middle Tennessee native Al Gore narrowly lost the region in 2000—a loss that ultimately cost him Tennessee, and the election. In contrast, it was one of the few regions in the country which voted more Republican than in 2004.[19] This is largely due to a growing social conservative trend in the region, particularly in the Nashville suburbs; some of the most politically active churches in the state are located there.

On the other hand, Barack Obama did improve relatively well upon John Kerry's performances in the traditionally Democratic cities of Nashville and Memphis. In the former, support amongst progressive whites led to a 3-2 victory for Obama in Davidson County.[19] In Memphis, heavy African American turnout ensured him the largest margin in the state in Shelby County, although far from enough to outweigh his losses everywhere else in the state. McCain, however, carried the third- and fourth- most populated cities of Chattanooga in Hamilton County as well as Knoxville in Knox County.

During the same election, at the state level, Republicans picked up four seats in the Tennessee House of Representatives and three seats in the Tennessee Senate to obtain control of both chambers of the state legislature for the first time since Reconstruction.

Technically the voters of Tennessee cast their ballots for electors: representatives to the Electoral College. Tennessee is allocated 11 electors because it has 9 congressional districts and 2 senators. All candidates who appear on the ballot or qualify to receive write-in votes must submit a list of 11 electors, who pledge to vote for their candidate and his or her running mate. Whoever wins the majority of votes in the state is awarded all 11 electoral votes. Their chosen electors then vote for president and vice president. Although electors are pledged to their candidate and running mate, they are not obligated to vote for them.[21] An elector who votes for someone other than his or her candidate is known as a faithless elector.

The electors of each state and the District of Columbia met on December 15, 2008, to cast their votes for president and vice president. The Electoral College itself never meets as one body. Instead the electors from each state and the District of Columbia met in their respective capitols.

The following were the members of the Electoral College from the state. All 11 were pledged to John McCain and Sarah Palin:

1. Sara Sellers
2. Jim Haslam
3. Wayne Cropp
4. Lisa Wheeler
5. Beth Campbell
6. Albert McCall
7. Shirley Curry
8. Marilucile Counce
9. Colin Richmond
10. Winfield Dunn
11. Chrystal Horn

• Presidency of Barack Obama