How many innocent Syrian civilians would be killed should the United States launch airstrikes against Syrian government radars, antiaircraft sites and air bases — obvious targets if the White House approved setting up the no-fly zone some members of Congress want? What would be the legal basis for such action?

These questions emerged last week as I listened to a Senate Judiciary subcommittee hearing devoted to the constitutional and counterterrorism implications of targeted killings by drones — unmanned aircraft. The countries mentioned were Yemen, Pakistan and to some degree Afghanistan.

Syria never became a focus because President Bashar Assad's military has advanced Russian fighter planes and air defense weapons. They make it impossible to use slow-flying drones, which can easily be shot down by relatively low-tech anti-aircraft weapons. The hearing did focus on civilians killed by remotely piloted aircraft and the resultant fear and anger.