Here's a brutal but to my mind persuasive case for allowing Iraq's civil war to take its course. It's from Foreign Affairs. Money quote:
As long as the Bush administration remains absolutely committed to propping up the government of Prime Minister Nouri al-Maliki or a similarly configured successor, the U.S. government will have limited leverage with almost all of the relevant parties. By contrast, moving away from absolute commitment - for example, by beginning to shift U.S. combat troops out of the central theaters - would increase U.S. diplomatic and military leverage on almost all fronts. Doing so would not allow the current or the next U.S. administration to bring a quick end to the civil war, which most likely will last for some time. But it would allow the United States to play a balancing role between the combatants that would be more conducive to reaching, in the long run, a stable resolution in which Sunni, Shiite, and Kurdish interests are well represented in a decent Iraqi government. If the Iraqis ever manage to settle on the power-sharing agreement that is the objective of current U.S. policy, it will come only after bitter fighting in the civil war that is already under way.
Withdrawal and redeployment are far more potent tools right now than the "surge." The latter seems to me to be a way for Bush to save face. But he shouldn't save face at the expense of increasing the long-term toll on Iraqi and American lives.