DURHAM, N.C. (AP) — Former CIA director and retired Army Gen. David Petraeus said Wednesday it’s worth a try for President Barack Obama to find a diplomatic solution for the showdown with Syria over chemical weapons, even with Russia taking the lead on setting in place a potential negotiated agreement.

Speaking in a question-and-answer session at Duke University, the former leader of U.S. military efforts in Iraq and Afghanistan said he’s still skeptical about the success of the Russian plan that would put Syria’s chemical weapons under international control for their subsequent dismantling in the middle of a civil war.