Partisan critics refuse to accept that war is tough and results are never perfect. They want it all wrapped up neatly at the end of the two-hour movie so we can all walk out of the theater feeling good.
When Petraeus gets to the Hill, he'll answer every question honestly. A disciplined soldier, he'll refrain from responding: Senator, that is a phony question -- and why haven't I seen your well-padded butt in Baghdad? He'll speak soberly -- detailing the indisputable gains on the ground, while acknowledging that many difficulties remain. He'll warn that the progress to date could still be reversed.
But the truth won't be enough in an election year. The theatrics won't come from the general, but from histrionic legislators. (That said, Sen. Hillary Clinton, having been caught in her lie about dashing through sniper fire, is unlikely to reprise her accusation that Petraeus is weaving fantasies.)