Rich Lowry diagnoses it: too much integrity for today's GOP:
The tricky thing about political leadership is that it has to involve some followership, too. Mitt Romney would have no chance to lead the Republican party as a relatively moderate northeasterner, because that’s not where the Republican party is. Nor would Rudy Giuliani, which is why he has distanced himself from many of his positions as mayor (although in not as jarring a fashion as Romney).
McCain's record is more conservative than that of both of those rivals, but, temperamentally, he's a go-it-alone crusader. That's not a good fit for leading a political party. McCain's political persona says, "Here I stand, I can do no other." The emphasis is always on his personal honor and integrity. When he was crusading for campaign-finance reform, McCain seemed to disdain political parties and offered in contrast his lone voice of righteousness... The flaws of the other Republican presidential candidates are so manifest that McCain could yet come back. But who can doubt that when John McCain essentially says he'd rather be right than president, he means it, and it could prove prophetic?
(Photo: Kevin C. Cox/Getty.)