Fouad Ajami is a senior fellow at the Stanford University’s Hoover Institution and author of The Syrian Rebellion.

"We wanted a clear message from Obama that the U.S. will continue to support democracy in Afghanistan," Fawzia Koofi, a lawmaker and human-rights activist, said this month. "It’s the only alternative to Talibanization."

Her honesty revealed the plain truth, without official pieties and doublespeak: The U.S. is quitting Afghanistan, and the morning after it does, the Taliban will begin the reconquest of that tragic land. After 11 years, and a toll of more than 2,000 Americans killed, 18,000 wounded, and the expenditure of more than $600 billion, what is perhaps the longest U.S. war is winding down.

That good war of necessity, set up as a willful contrast to the war of choice in Iraq, is in Washington’s rearview mirror. No stirring prose attends that war. When Afghan President Hamid Karzai came to Washington for an official visit on Jan. 11, the mood was sober and resigned. He could promise immunity for the U.S. forces that would stay in his country, but this would not change the course of things. A cunning warlord -- a job requirement -- Karzai knew it was the endgame in Kabul for the Americans.

U.S. President Barack Obama, who had made Afghanistan his just war of necessity, had won re-election and he insisted that the conflict was meant to avenge what befell the U.S. on Sept. 11, 2001. A year into his first term, he had doubled down in Afghanistan, ordering a surge of his own. The potential damage to his presidency from war in the Hindu Kush was contained. The Republicans couldn’t outflank him, for they, too, knew that this was an unpopular war...