President Obama will lay out his plan to counter the Islamic State on Wednesday night, and we'll judge the strategy on its merits. But the mere fact that Mr. Obama feels obliged to send Americans to fight again in Iraq acknowledges the failure of his foreign policy. He is tacitly admitting that the liberal critique of the Bush Administration's approach to Islamic terrorism was wrong.

Recall that Mr. Obama won the Presidency by arguing that the U.S. had alienated the world and Muslims by recklessly using force abroad. We had...