Yes, George W. Bush and John Kerry are cousins. Ninth cousins twice removed, but still cousins.

They're also both related to Dracula.

Bush and Cheney are also related, as are Bush and Colin Powell. I also have a long list of other cousins.

Something else you may not have known, which is on that long list: The only two father-son combinations to be president were John and John Quincy Adams, followed by George H. W. and George W. Bush. That's pretty widely known. But what you may not have known is the Bushes are distantly related to the Adamses (5th cousins), which makes them as closely related as Teddy and Franklin Roosevelt.