Would the US actually cease to exist after the nuclear war? (1980-1990)

This is almost cliche in fiction; after nuclear war the US simply ceases to be, instead of existing as entity with greatly dimished capacity.

Now, there are brilliant exeption to this cliche rule.
In the movie "Threads", altough the US is not shown, Great Britain can be seen as mix of North Korea with Somalia&Eritrea, but basic structure of governance continue to exist under martial law. Though vision from that movie is frequently described as fate worse than death, taxes are still as sure as death in that world xd

Likewise, the US in "The day after" seems to basically still exist, though US Army is shown as unable to properly protect refugee camps and farmers. (but this US army also seems to respect human rights, more or less)

But there are not many such examples.

It seems to me that as long as a few millions of people remain alive in the North America, and as long as some military & FEMA command&control facilities remain operational, the US should be able to exist as geopolitical entity. Would you agree?

Note that this may be easier with human rights thrown into trash and with liberal use of remaining WMD (chemical weapons?) against farming communities and towns that would try to secede (especially against these that would cease paying taxes/tribute to local military administration). Advanced military hardware should remain operational for at least 10-20 years even without spare parts; some trucks and downsized airforce may be viable for a 50-100 years even without heavy industry.
 
Top