With the 20th anniversary of the Afghanistan war now just around the corner, Americans might reasonably wonder whether the nation’s longest war is ever going to end. After carefully considering the question, two retired four-star generals, two former U.S. senators, three ambassadors, a former national security adviser, and several other august personages have weighed in with an opinion: not if they can help it. Policy wonks who have been waiting with bated breath can now exhale: the congressionally mandated Afghanistan Study Group (ASG) has published its findings. The panel of grandees...