We do not need to re-invade or restabilize Iraq to deal ISIS a blow and help its victims, because Kurdistan is already relatively stable, and the line of conflict is relatively clear. And the Kurds themselves, crucially, are a known quantity with a longstanding relationship to the United States — something that wasn’t on offer in Libya or Syria.

So our intervention in northern Iraq has a limited, attainable objective: Push ISIS back toward the Sunni heartland, allow its victims to seek refuge in Kurdish territory and increase the Kurds’ capacity to go on offense against the caliphate.

But if this president is thinking strategically, instead of just conducting a humanitarian drive-by, this intervention could also set the stage for a broader policy shift. Swiftly or gradually, depending on political developments in Baghdad, an independent, secure, well-armed Kurdistan could replace an unstable, perpetually fragmenting Iraq as the intended locus of American influence in the region.