Well, I'm simplistic because I certainly believe that our deterrent has done just that, and kept us safe for the past 70 years. No one is or has suggested that we fire it first, that of course is out of the question, but I do believe that the knowledge that if the worst happened the nation responsible can be assured that from a submarine deep in the ocean far away from these shores, they will regret such an action, and knowing that will, and probably has, concentrated the mind of countries that wish us harm.