u.s.-backed forces on the ground help in a broader strategic sense? >> well, phil, the broader strategy, as you know, is embedded inside a global strategy. right now the americans are make-very clear that isis in our cross hairs. that's what our conduct of the campaign in syria is designed to take on, is take on isis and defeat them. this other effort that came up in the midst of that had to be addressed. because it address as vital national interest of ours that chemical weapons not be used, the bar not be lowered by the assad regime so that this is commonplace. we had to make a very clear statement on this. >> i would just add that -- something that we always pay attention to, the environment