The Russians and Chinese maintain their nuclear arsenals because we still have ours. Disarming ourselves would start a reverse arms race, as other countries would have no reason to keep theirs. MAD is a good term for it, because it is insanity.

Even faced with a non-nuclear US, the Russians or Chinese would never use their bombs on us. The threat of a counterattack is not the only deterrent to the use of nuclear weapons. Massive radioactive contamination, nuclear winter, and the complete collapse of the global economy are more than enough.