We’re being had. Again. For six years, President Obama has endeavored to will the country into accepting two pillars of his alternative national-security reality. First, he claims to have dealt decisively with the terrorist threat, rendering it a disparate series of ragtag jayvees. Second, he asserts that the threat is unrelated to Islam, which is innately peaceful, moderate, and opposed to the wanton “violent extremists” who purport to act in its name. Now, the president has been compelled to act against a jihad that has neither ended nor been “decimated.” The jihad, in fact, has inevitably intensified under his counterfactual...