and charles glaser, not related to bonnie glaser, is professor of political science and director of they and conflict at george washington university. welcome to all three of you. thank you very much. richard haass, let me start with you. has u.s. policy of ambiguity about whether it would defend taiwan from chinese invasion run its course? >> well, it's worked well for about four decades. chinese, i've not been able to dismiss the possibility we would come to taiwan's defense. taiwan could not be assured we would, and that's kept everybody essentially on their heels a bit. the problem now is china has built up its military significantly. it's got real capabilities to overwhelm taiwan if left alone. and there's real doubts in china's mind about america's willingness to come to taiwan's aid. they look at what's happened in afghanistan. they look earlier what we did with the kurds. the red line and syria. how we didn't respond to hong kong. how we didn't respond to crimea. so there's a lot of people in china who think there's a major opportunity. so i would essentially say we need to be m