President Obama was right to order military action to prevent a potential genocide in northern Iraq and to stop forces of the al-Qaida-derived Islamic State from advancing on Baghdad or the Kurdish capital of Irbil. However, the steps the president authorized on Thursday amount to more of his administration's half-measures, narrowly tailored to this week's emergency and unconnected to any coherent strategy to address the conflagration spreading across the Middle East.
While U.S. airstrikes and drops of supplies may prevent the terrorist forces from massacring the Yazidi sect or toppling the pro-Western regime in Kurdistan, Mr. Obama lacks a plausible plan for addressing the larger threat posed by the Islamic State. In recent weeks, senior U.S. officials have described the danger in hair-curling terms: The Islamic State forces, which have captured large numbers of U.S.-supplied heavy weapons, threaten not only the Iraqi and Kurdish governments, but also Lebanon, Turkey and Jordan. With hundreds of Western recruits, they have the ambition and capability to launch attacks against targets in Europe and the United States.
Yet by the White House's own account, the measures ordered by Mr. Obama are not intended to defeat the Islamic State or even to stop its bloody advances in most of the region. Instead they are limited to protecting two cities where U.S. personnel are stationed and one mass of refugees. The hundreds of thousands of people in Syria, Lebanon and elsewhere threatened by the al-Qaida forces will receive no U.S. protection. Nor will the terrorists' hold over the areas they already control, including the large city of Mosul and nearby oil fields, be tested by U.S. airpower.