Snipers line the rooftops across Falluja, waiting for a chance to shoot at government soldiers, should they try to invade. Homes have been wired to explode, too, just in case the government rushes the city. And roads have been studded with countless steel-plated bombs, of the type that killed so many American soldiers here. Falluja — and the rest of Anbar Province — perhaps more than any other locale in Iraq, embodies the lengths the United States went to tame a bloody insurgency unleashed by its invasion. But now, much of the region is again beyond the authority of the central government and firmly in the control of the Islamic State of Iraq and Syria, a jihadist group that is so radical it has broken with Al Qaeda, in part because it insisted on being allowed to indiscriminately kill Shiites. That reality, which the government appears powerless […]