There's one more big question mark in this war and it's the scariest one. It is about whether Putin or one of his successors might be willing to use nuclear weapons if Russia's back is really up against the war. What we must remember is that this is not the first time a nuclear armed country is considered using nuclear weapons against a non-nuclear armed country. So for all of those reasons, as the Russian lines begin to collapse, I do worry that nuclear use is a possibility. But I absolutely don't think it can be taken for granted.