stop him from using these again? if it's not regime change, it may well incite the russians to become more involved, the iranians to become more involved. it may well incite gas attacks on tel aviv or israel. what happens then? will israel feel restrained this time the way they did in the gulf war? or will israel respond in not just a proportional fashion but an overwhelming fashion to now obliterate as much of iran's military capacity if iran gets involved? there's a lot of unknowns about this. eisenhower said that when the violence begins, you can throw out all your plans. but you certainly have to think about before you begin offensive actions what the possible ramifications are if this spins out of control. >> i just want to be precise, senator. are you leaving open the possibility, albeit remotely, that perhaps the rebels were responsible for this chemical gas attack as opposed to the regime of president bashar al assad? >> i've seen no evidence on