responsive leg and they can be launched at a moment's notice. you mentioned the targeting challenge of our icbm force, and what that targeting challenge poses for our adversaries. could you explain that further? >> ma'am, in my review of the triad that you brought up here, senator, i looked at each one of those legs, is it necessary. and i haven't had access to all the classified data, but i had a fair amount of background on this. and some of the aspects of why we have a triad have not changed. so in looking at each leg of it, with the icbm force, it's clear that they are so buried out in the central u.s. that any enemy that wants to take us on is going to have to commit two, three, four weapons to make certain they take each one out. in other words, the icbm force provides a cost composing strategy on an adversary.