As Prof Schelling argues, former nuclear nations cannot unlearn their nuclear expertise and will remain "latent nuclear powers" with ability to rapidly mobilize both fissile materials and other required materials and knwoledge to assemble their nuclear capacity. And on the face of the slightest threat of war, they would have the temptation/incentive/pay-off to defect from any disarmament agreement.
The painstakingly established rules of the deterrence game, with its concept of strategic readiness - configure strategic nuclear forces to provide reasonably comfortable assurance against surprise or preemption, with appropriate command and control - among all the actors concerned, will need to re-develop before the stability of a strategic equilibrium can be achieved. He writes,
"In summary, a "world without nuclear weapons" would be a world in which the United States, Russia, Israel, China, and half a dozen or a dozen other countries would have hair-trigger mobilization plans to rebuild nuclear weapons and mobilize or commandeer delivery systems, and would have prepared targets to preempt other nations' nuclear facilities, all in a high-alert status, with practice drills and secure emergency communications. Every crisis would be a nuclear crisis, any war could become a nuclear war. The urge to preempt would dominate; whoever gets the first few weapons will coerce or preempt. It would be a nervous world."
A matrix of the strategic game, involving India and its ex-nuclear partners, under the aforementioned conditions would look like this
In other words, a world without nukes has all likelihood of being a throw-back to the uncertainty of the immediate post-war era. In due course, the non-proliferation movement will get revived to contain the then covert nuclear programs of the same violators. History would have turned the full circle.