The standoff between President Bashar al-Assad and Syria’s opposition seems poised to spiral into a full-fledged civil war. In the wake of a failed intervention by the Arab League, protests have spread from Homs and Hama to the capital, Damascus. In a televised speech last week, al-Assad said “We will defeat this conspiracy without any doubt.” There have also been reports of Russia supplying arms to the Syrian government.   George A. Lopez is professor at the Krock Institute of International Peace at the University of Notre Dame and co-author of “Putting Teeth in the Tiger: Improving the Effectiveness of Arms Embargoes.”