...The political calculus of such maneuvering among America's Western allies is unclear. Last year, British Prime Minister David Cameron experienced one of the most humiliating defeats of his premiership when a motion to join potential airstrikes against Bashar al-Assad's government was rejected by Parliament. However, the atrocities committed by ISIS since its overrunning of broad swathes of Syria and Iraq, have seemingly galvanized Cameron to press for action. In a recent opinion piece in the Sunday Telegraph, Cameron said that Britain was "in the middle of a generational struggle against a poisonous and extremist ideology."

Late Monday, the Pentagon began sending surveillance drones on flights over Syria to gather intelligence on ISIS positions after Obama approved their use over the weekend. The Times cited a report from the Syrian Observatory for Human Rights that “non-Syrian spy planes” on Monday carried out surveillance of ISIS positions in the eastern province of Deir Ezzor.

The Assad government in Damascus has warned the U.S. not to strike ISIS positions on Syrian territory without asking permission. However, on Tuesday, State Department spokeswoman Jen Psaki emphatically rejected that condition, telling reporters "We're not going to ask permission from the Syrian regime." However, Psaki also noted that Obama had not made a final decision on whether to approve airstrikes in Syria....