U.S.-led airstrikes designed to serve notice on Islamist extremists in Iraq and Syria have also delivered a sobering message to Washington and its allies: Breaking the militants’ grip will be every bit as difficult as they feared. As the U.S. prepares to launch a ground war by proxy forces in Syria and Iraq, there are signs that the air campaign is disrupting militant group Islamic State. Fighters are fleeing their bases, they travel at night and in smaller units and are cutting back on cellphone and radio communications to evade detection, according to U.S. officials and opponents of the group on the ground. However, Islamic State appears to have largely withstood the airstrikes so far and with scant pressure on the ground in Iraq and Syria, the militants have given up little of the territory they captured before the campaign began. ( Opinion: The Next Front Line in the […]