At what point does all this start to, you know, worry us?

Maybe when they start killing Americans again. Until then, the reflex political reaction regarding the return of AQI is to insist that it is a local group with mostly local ambitions, and that it is largely a reaction to Iraqi Prime Minister Nouri al-Maliki’s purportedly anti-Sunni policies. Nothing in life is harder to unseat than a settled and comfortable assumption.

Still, assumptions must inevitably run up against facts. No ostensibly “local” al Qaeda branch has ever remained local for long, a point brought home last month when Somalia’s al-Shabaab went on an epic killing spree at Nairobi’s Westgate Mall.

By doing so little to stop the spiraling chaos in Iraq and Syria, the administration isn’t keeping America out of harm’s way. It is allowing the next generation of jihadists to incubate, hatch and grow, mostly undisturbed by us. For more on how that works out, think about U.S. policy toward Afghanistan, 1989-2001.

It’s also a fact that, despite his reputation as an inveterate sectarian, Mr. Maliki still runs a more-or-less democratic state, an American achievement worth trying to preserve.