The intelligence gathered by U.S. military surveillance flights over Syria could support a broad bombing campaign against the Islamic State militant group, but current and former U.S. officials differ on whether air power would significantly degrade what some have called a “terrorist army.”

Further complicating the plans, any military action against Islamic State militants in Syria would also have the effect of putting the U.S. on the same side as Syrian President Bashar Assad, whose ouster the Obama administration has sought for years.

The Islamic State group is headquartered in the Syrian city of Raqqah and has been fighting the Assad government, though it is also at war with moderate rebels who have received arms and funding from the U.S. The group, which controls a large part of eastern Syria, crossed into Iraq earlier this year and has captured much of the Sunni sections of northern and western Iraq, prompting U.S. airstrikes to protect American personnel in that region. […]