Kerry is giving up nothing here, the Swift Boat ads are more damaging to him than this is to Bush. I would not be suprised at all if that was the very purpose of the Moveon ad, to be used as a throwaway to attempt to box Bush into denouncing the Swift boat ad.
President Bush should thank John Kerry and say that the moveon.org adds false accusations have all been investigated and have no foundation in fact.
Then he should say the Swiftboat Vets aren't Republicans but Kerry's fellow servicemen who have a personal problem with John Kerry, and anyway Kerry can do what President Bush did to disprove those false charges and sign a DD SF 180 and release all his service records.