Under this title Noemie Emery explains the effect of the Iraq war on the candidates and offers this suggestion for a McCain ad:

Cut to Obama, praising his own judgment.

Cut to Obama, opposing the surge, repeatedly, as it is bound to prove useless.

Cut to Obama after the surge has succeeded, claiming he had always said that adding additional troops would improve security.

Cut to Obama telling ABC News's Terry Moran that he would vote against the surge all over again, as he was opposed to the president's overall strategy.

Cut to Obama again, touting the strength of his intuition and judgment.

From the GOP's standpoint, the ads write themselves. (Snip)

McCain needs Iraq to be won, as it was his war and he knew how to fight it, but not won so thoroughly as to be handed off risk-free to the neophyte challenger. Obama needs the war to be won to make it safe to elect him, but if it is won it indicts his own poor judgment and deprives his party of its favorite issue and most emotional line of attack on his rival, and on Bush.