Are you talking forced euthanasia/population reduction, one-world government, a loss of the trade status of the US dollar , . . . .
Or . . . .
Some real serious Sh!t?
If that situation unfolded & most major powers were spent & enough damage/atrocities were burned into the world's consciousness - THEN
It seems inevitable that nature abhors that sudden vacuum - and a new centralized power structure would quickly emerge - it would probably cite a simple , universal moral code (like Nurenburg Code or Jewish Noahide Law or maybe something more boastful like the "new Ten Commandments" unveiled about a year ago) -- and the electronic based economy would include limited food access and more extensive surveillance and data links to AI,
I think the governing structure after a major war between current powers a would return to.a Holy Roman Empire type Absolute Monarch & High Priest
People would be networked into a new Internet of Things (biological infrastructure) - and possibly have access to genetic upgrades/modifications as incentive to "submit to the post-nuclear borg-party
Kind of what I picture -
For some reason I don't believe we will see all out nuclear exchanges - but limited and starkly horrifying blasts that will be a call for permanent disarmament and international oversight + authority .:.:so current institutions like World Bank, IMF, WHO, UN, Vatican, a newly emerged united religious initiative, population based NGOs --- would become brokers of oversight and control
And I fully expect a more damaged genetic landscape as gene editing , cloning & chimeras become more common
The full "alien disclosure" - whatever that may look like - would be post-hyper-war
And i bet we have 3 Sugar Bowl victories by then too, yall fools!!