Obama would be wise to ignore Klein and decide not to play chicken with the numbers. Afghanistan will not magically right itself, particularly now as Petraeus can inflame the violence as much as he pleases.
On Afghanistan, either the general or the president (or both) is a huckster for this high-interest war. We'll know from the White House's response to this military media blitz just who the huckster really is.
It's too bad that General Petraeus is attempting to suppress democratic opinion. But Congress, and the people running for Congress, understand full well that this is a fight the American people are ready to have.