What Happens to Deterrence as Nuclear Weapons Decrease Toward Zero?

Steps reducing reliance on deployed nuclear weapons en route to zero will be discussed. They include broadly enhancing cooperation and transparency agreements beyond the provisions for verifying limits on deployed strategic nuclear warheads and delivery systems in the New START treaty. Two questions that will be addressed are: What conditions would have to be established in order to maintain strategic stability among nations as nuclear weapons recede in importance? What would nuclear deterrence be like in a world without nuclear weapons?