"Now his [Bush's] credibility is tied to theirs"
and this is a problem WHY?
Because John McCain made it Bush's problem when he told him to denounce the ads two weeks ago.
Some analyst nailed it yesterday when he said all the elements had to be in place for Kerry to pull this one: Swiftee ads, connections to GOP even if they aren't directly to Bush, McCain denunciation, 527 ad attacking Bush's service, and Kerry's denunciation of that ad.
Bush would have lost nothing to denounce the ad in the beginning. Whoever advised him not to will be the culprit if he loses.