Today’s Washington Post op-ed by 12 Army captains who served in Iraq is a sobering but welcome contribution to the voluminous literature on what went wrong in Iraq, and what we should do next. The entire article is worth reading, but the concluding paragraphs boil down the essential points:

There is one way we might be able to succeed in Iraq. To continue an operation of this intensity and duration, we would have to abandon our volunteer military for compulsory service. Short of that, our best option is to leave Iraq immediately. A scaled withdrawal will not prevent a civil war, and it will spend more blood and treasure on a losing proposition.

America, it has been five years. It’s time to make a choice.

This is how the debate over Iraq should have been framed at the outset — before Congress voted to grant the president authorization to use force.

Success in Iraq was always uncertain. How uncertain depended, in part, on the amount of effort we were willing to exert in the endeavor; but it also depended on a number of factors well beyond our control. And there is no evidence that George Bush ever seriously contemplated the costs of waging war for five years — he merely asserted on the eve of war that the costs of inaction outweighed the costs of action.

For a time, the American public went along. Now, five years on, a solid majority disagree. In poll after poll, Americans say that the costs that we have already paid in this war far exceed whatever benefits we might hope to derive from it. And they are looking to cut our losses.

They are unlikely to embrace a further escalation of the conflict, particularly one that entails the draconian step of reinstituting the draft. And they should not do so. As the Army captains concede, we might still fail, even if we flood Iraq with tens or hundreds of thousands more American troops. Hardly a ringing endorsement for that option.

If our national survival hung in the balance, if our very existence was threatened by an escalating civil war in Iraq, we would be spared such discussions: we would invest what was necessary, and worry about the consequences later.

But Iraq always was, and always will be, a war of choice. We should choose to terminate the mission, and refocus our attention — and, where appropriate, our still-strong military — on the enemies who struck us on 9/11.

That the choice is clear does not imply that the choice is easy. The ramifications of a U.S. withdrawal are likely to be horrible in the short term, especially for the many Iraqis who risked their lives by cooperating with the American forces, and the many more who are likely to be caught in a worsening civil war. We should do what we can to help the Iraqis, especially those who have helped us.

There are still other concerns. The real risk of that civil war spreading beyond Iraq’s borders, actions that could spawn a wider regional conflict, requires that a U.S. military withdrawal be combined with a diplomatic offensive to encourage all of Iraq’s neighbors to take prudent steps to contain the violence. Our problem is also their problem; they would be wise to cooperate with us, and with each other, to prevent a far worse catastrophe from unfolding there.

But such considerations do not change the basic calculus for the United States: given that we should not be willing to pay whatever might be needed to win, recognizing all the time that victory is uncertain, and might take years to achieve, we should leave.

I commend these 12 soldiers for their service in Iraq; and, although it can’t compare to their courage and sacrifice over there, I commend them for weighing in on the issue.