The Marines in Helmand, like U.S. forces throughout the country, have embraced counterinsurgency methods to befriend and protect the local population. They carry cash to buy sodas and food in the local markets. They work with the provincial government and tribal leaders to provide services for the people. “I’ve bought more friggin’ pomegranates than you can imagine,” says the Marine commander, Brig. Gen. Larry Nicholson.

It’s too early to be sure, but this people-friendly strategy seems to have helped. The local provincial governor, Gulab Mangal, says security is better now in some areas of Helmand than it has been in a decade. “We need the Americans at this moment,” he told me.

So what should Obama do? I think he should add enough troops to continue the mission he endorsed in March to “reverse the Taliban’s gains” and improve security in Afghanistan’s population centers. I don’t know whether the right number is the roughly 40,000 that Gen. Stanley McChrystal has recommended, but it should be the minimum number necessary. The additional troops will come at a steep political price, at home and abroad.