For the nation, the president’s best course would be to protect and capitalize on the progress we have made by maintaining troop levels and offensive operations in Afghanistan until the job is done, whenever that is. Whether Obama will follow this course, or at least order only a token withdrawal to minimize the damage of his imprudent 2009 pledge, we will soon see.

There should be no mistake that a politically driven withdrawal of substantial U.S. forces will squander the victories won in Afghanistan since the 2009 surge. It will signal to the Taliban and Al Qaeda that their long travail is nearing an end. And it will signal to radicals in Pakistan and elsewhere that they too can act against the U.S. ultimately with impunity. All of these results will endanger not just the United States but peace and security worldwide.