On what basis are you fantasizing about demilitarization of a nuclear state? How would that work? I hate Putin as much as the next person, but nothing will happen to the Russia proper -- they'll start throwing nukes, tactical first, then strategic.

Peace treaties in the past contained all sorts of demilitarization clauses. It is not unprecedented.

Counties sign such peace treaties when they lose hard enough to start losing their territory proper, or they are forced to capitulate, are occupied. How would a nuclear state lose their territory proper? There were indeed various peace treaties in the past, but not a nuclear state losing their territory proper.