We (the USA and Great Britain) already have plenty of missiles with that capability. And each of those SLBM's can "deliver" up to 14 warheads, each 1/2-megaton yield (currently limited to 8 by a treaty with Russia).
If you're going to violate the sovereign airspace of another country (which would possibly include China and Russia) it better be for a damn good reason and you should be prepared for the consequences. So nukes instead of nick-knacks because you will be starting (or responding) to some serious aggression.
This post was edited by Salt and Red Pepper at July 30, 2017 4:48 PM MDT