We are dealing with an enemy that believes, in the words of bin Laden, “Death is better than living on this earth with the unbelievers among us.” The al-Qaeda Charter, for all its malevolence, has the virtue of clarity. It states, “there will be continuing enmity until everyone believes in Allah. We will not meet [the enemy] halfway and there will be no room for dialogue with them." As if to reinforce the point, an al-Qaeda training manual says this:

"Islam does not coincide or make a truce with unbelief, but rather confronts it. The confrontation that Islam calls for with these godless and apostate regimes, does not know Socratic debates, Platonic ideals nor Aristotelian diplomacy. But it knows the dialogue of bullets, the ideals of assassination, bombing, and destruction, and the diplomacy of the cannon and machine-gun."

We best take them at their word.

Iraq and Afghanistan are separate theaters in a larger global struggle. The United States can leave Iraq before a decent outcome is attained – but if we do, the wider war will not end; it will only intensify – but with the United States in a substantially weaker situation.

An American defeat in Iraq would reinforce the impression among jihadists that the United States is the “weak horse,” that when bloodied we will flee, and that in the end, their will is simply stronger than ours. And if the critics have their way and deny General Petraeus the time he needs to help bring about a decent outcome in Iraq, the jihadists will be right.