Dempsey spoke at a lunch Tuesday hosted by The Christian Science Monitor. He said establishing a no-fly zone could also get the United States deeper into the civil war between President Bashar Assad and Syrian rebels.
Creating the no-fly zone would mean gutting Syria's defenses against air attack, creating a plan to rescue downed U.S. pilots and being prepared for a counterattack that might take the form of a bombing or other act of terror outside Syria, Dempsey said. He said only about 10 percent of the casualties now inflicted on the rebels come from airstrikes.
Dempsey posed another consideration: "So, the question then becomes, if you eliminate one capability of a potential adversary, will you be inclined to find yourself in a position to be asked to do more against the rest?"
2014: The Year in Music [PHOTOS]