If Al Gore had won his home state of Tennessee, he would have been POTUS.

[bluestateguy]

8. Gore was caught napping

In 1992 the Clinton-Gore ticket won Tennessee 47%-%42, and only by 48%-%46 in 1996. The Clinton camp never took that state for granted and they sent Gore in to campaign there many times in those elections.

Then in 2000 the Gore people just assumed that Tennessee would be a pretty easy win and didn't pay it much attention. When polls in the summer warned of a dead heat in the state, the Gore people blew it off and figured that Tennessee would just come around on its own. By early October the Gore campaign realized they were in trouble in their home state and Gore was busy campaigning down there, which made for some embarrassing headlines that did not project a lot of strength ("Gore forced to shore up home state", etc.).

A similar error was made in West Virginia. Gore got caught napping and the Bush people were there to take advantage.

James Polk lost his own Tennessee in 1844, BTW.