John McCain's Achilles Heel

No, it's not all his lobbyist buddies or that woman who looks strikingly like his wife. It's President Bush, who in a new national poll has surpassed Richard Nixon as the modern president with the highest negative rating.

Some 52 percent of those surveyed place Bush at the bottom end of the scale as either "below average" or a "failure", compared to 50 percent who said the same about Nixon. Bush also beats out Nixon on the failure scale - one in three Americans (33 percent) say Bush is a failure as a president, up from 30 percent who said the same last year. Most Democrats (60 percent) view Bush as a failure, but half as many independents (29 percent) feel the same, compared to just 7 percent of Republicans.

McCain has been chary to criticize Bush, and its hard to see how he'll get much traction beyond the shrunken Republican base if he doesn't.