RPC John McCain (21 images)

Former President George H.W. Bush, right, and Republican presidential candidate John McCain talk on the tarmac at Hobby Airport February 18, 2008 in Houston, Texas. Bush officially endorsed McCain in the race for U.S. President. (UPI Photo/Ian Halperin)

Sen. John McCain (R-AZ) waits for the start of a Senate Armed Service Committee mark up on military combatant detainee legislation, in Washington on September 14, 2006. (UPI Photo/Kevin Dietsch)

Republican Senator John McCain makes a stop at campaign headquarters while campaigning for the Iowa Caucus in Urbandale, Iowa on January 2, 2008. (UPI Photo/Laura Cavanaugh)

U.S. President George W. Bush and Republican presumptive presidential nominee Sen. John McCain (R-AZ) shake hands after speaking to the media in the Rose Garden of the White House on March 5, 2008. Bush endorsed McCain's candidacy and pledged to support McCain during the campaign. (UPI Photo/Roger L. Wollenberg)