Continued from page 1

The conflict has left more than 4 million people in need of humanitarian assistance, including 2 million Syrians who have fled their homes inside the country, and created more than 630,000 refugees. The refugees are pouring into Lebanon, Jordan, Iraq, Turkey and Egypt. Most are women and children.

Mr. Kagan predicted that it would take the Assad regime using chemical weapons before the Obama administration responds more forcefully to the conflict.

“Anyone who thinks that Assad will go down without using every weapon, that seems to me to be a fool’s errand,” he said.