Divide and conquer is a fantastic strategy against a stronger opponent and Putin is playing this like a master.
Maybe America's time has run out, but I for one would like to see the USA remain strong and united, I fear this may already past the point of no return and with ever day that goes by and this madness continuous you'll be looking wistfully back at those 'terrible' years under Obama, Bush, Clinton and so on.
And in a way that is the most vexing of all this: Trump is lying through his teeth to get those votes, he will not be able to give his voters what he wants but in the meantime the clock is going backwards at a rate of about 4 years per week that this guy is in power.
America's signature under a treaty (always a dicey thing) is now worth absolutely nothing, international relations are damaged for years to come, re-armament will be on the agenda in lots of places that were better off without the ability to slaughter their neighbors and so on. Think of it as the roll-back of 50 years of diplomatic policy that kept a large chunk of the world - the USA included - stable and prosperous.