It’d be fun to watch the three try to disarm India, and trigger World War 3!
The U.S., Russia and China would have to agree to disarm. India may well go along with that. If not, there wouldn't be an invasion but a blockade. North Korea resists most forms of persuasion by the U.S. but if China cut all links with North Korea it would fall apart. China and Russia could destabilize Iran without setting foot there.
‘fun to watch’
=deterrent