McKinnon, a lifelong Democrat until he decided to team up with Bush, developed a bond with McCain over their shared belief in the need to remain committed to the troops in Iraq. McKinnon helped organize McCain’s last book tour and has traveled extensively with the senator, offering media advice to the candidate for much of the last year. But he wrote a memo to the campaign in January, explaining that he would quit if the general election pitted McCain against Obama. McKinnon wrote that while he opposed Obama’s policies, especially on Iraq, he felt that the Illinois senator–as an African-American politician–has a unique potential to change the country. Therefore, McKinnon argued, he wanted no part in any efforts to tear down Obama’s candidacy. (McKinnon, who has previously told friends he was inspired by Obama’s autobiography, refused to comment on the memo, as did Brian Jones, McCain’s communications director; Obama’s campaign said that the senator had never met McKinnon.)

But McKinnon’s views have not stopped McCain from launching attacks on Obama. Last month, the two senators traded personal barbs over Iraq. McCain accused Obama of having a policy of surrender on Iraq, while Obama accused McCain of being out of touch with reality in Iraq. The skirmishing at the staff level was fiercer still; an unnamed McCain aide suggested that Obama wouldn’t know the difference between a bomb and a bong. –With Holly Bailey