The better the west does in Ukraine the closer it pushes Russia to catastrophic defeat, says Peter Bergen. The risk of a nuclear event grows the closer Russian forces come to defeat our perception of that risk relative to what it might be is one of the driving aspects of the conversation the west. escalation management remains an important imperative and I think four should neither be dismissive and hand-waving about this base saying well Russians just won't use nuclear weapons because those not a potential outcome.