how did we get here, derek chollet. >> well, it's a very difficult confluence of issues. it's a proxy war being fought by many countries in the region. and, of course, the russians, with many different interests at play, it's a brutal regime in the assad regime that is willing to take any measure, no matter how immoral or war criminal acts to persecute its goals. and it's very much driven by fears in the united states, legitimate fears, i believe, about escalation of any u.s. military involvement, and what that may lead to in terms of an enduring u.s. commitment, military commitment inside of syria. >> woodruff: nicholas kristof, how did we get here? >> well, i think that president obama resisted the suggestions by hillary clinton, by david petraeus, and others to become more engaged, partly because it seemed plausible, in 2012 or even 2013, that assad was going to fall anyway and, you know, why get engaged if what we want is going to happen anyway. and that was, indeed, plausible, but it also proved wrong. and i think also more broadly, in a place like syria, you know, t