On impact of US support for Syrian rebels

"Would the United States providing more arms to the FSA have accomplished these goals? The academic literature is not encouraging. In general, external support for rebels almost always make wars longer, bloodier and harder to resolve (for more on this, see the proceedings of this Project on Middle East Political Science symposium in the free PDF download). Worse, as the University of Maryland’s David Cunningham has shown, Syria had most of the characteristics of the type of civil war in which external support for rebels is least effective. The University of Colorado’s Aysegul Aydin and Binghamton University’s Patrick Regan have suggested that external support for a rebel group could help when all the external powers backing a rebel group are on the same page and effectively cooperate in directing resources to a common end. Unfortunately, Syria was never that type of civil war."