The U.S. is doing a mediocre job training the Afghan army. Here’s a plan for doing it better.

Two things are clear about U.S. policy toward Afghanistan. First, we are steadily withdrawing our combat troops over the next two years. Second, we have no plan for ensuring that the place doesn’t fall apart afterward.

A study published today by the Center for a New American Security, a Washington think tank, calls this a “civil-military disconnect.” Political leaders here and in Afghanistan have decided we’re getting out in 2014. But U.S. military commanders on the ground act as if they’re staying forever. They take the lead in most military operations, while Afghan soldiers are being trained in a rote manner, so that nobody knows whether they’ll be ready to take over the fight until they’re left holding the bag.

Retired Lt. Gen. David Barno and Andrew Exum, the study’s two authors—as well as a separate article in Foreign Affairs by John Nagl, the president of CNAS—propose a shift in strategy to ensure that we leave Afghanistan in the hands of a capable local force. First, they argue, the U.S. should create a special corps within the U.S. Army and Marines to train and advise the Afghan army. Second, we should embed small teams from these corps within Afghan army units, so they can train and advise the Afghans on the job.

This is a bigger shift than it might seem, and under the circumstances it’s a good idea, not only for the war in Afghanistan but the future of the U.S. military more broadly.

At the moment, some U.S. units “partner” with Afghan units, but, when things get rough, the Americans take over. It’s a lot easier that way, and less risky. The problem, though, is that the Afghans never get much practice at developing the mindset or practicing the combat skills that they’ll need when they’re alone.

There are obstacles to this sort of shift, and they all reside within the U.S. military. The Army and Marine Corps bureaucracies have resisted the occasional effort to develop a dedicated advisory corps. They see their main mission as combat, and while they will take on other missions (as they’ve done for the counterinsurgency campaigns in Iraq and Afghanistan), they oppose restricting any of their units to non-combat tasks.

But here’s the problem: Not every soldier is well suited to train or advise other soldiers, especially other nations’ soldiers. “Security-force assistance,” as the task is formally called, is an art in itself; its practitioners need special training to do the training.

Here’s another problem: Since the Army and Marines tend to promote officers on the basis of their performance in combat, few officers would want to join this advisory corps, even if it existed.

So the study proposes two fixes to these problems. First, the Army and Marines should create a new command, empowered with the necessary mandates, to oversee, select, train, equip, and deploy the trainer-advisers. Second, the promotion boards should be required to reward a certain number of trainer-advisers each year along with the more conventional soldiers.

This is not an entirely new idea. When Gen. Martin Dempsey was briefly Army chief of staff, before President Obama kicked him upstairs to be chairman of the Joint Chiefs of Staff, he entertained the idea of not quite an advisory corps but rather a corps of regional experts, who would be trained and promoted separately from combat soldiers. Their missions could have included training and advising foreign armies. It is unclear where Dempsey’s replacement, Gen. Ray Odierno, stands on the issue.