"I think ISIL made a huge strategic blunder with the video of the execution of the American. That really does provide a new and graphic basis for the president to take action against ISIL. In other words, it's inarguable they present a threat to America," said Charlie Dunlap, a law professor at Duke University who retired in 2010 as a major general in the U.S. Air Force Judge Advocate Corps.
"I think the video provides political leaders not just in the U.S. but elsewhere with the ready rationale for their publics. It's very easy to convey the threat ISIL presents when you have a video like that," he said.