You perfectly described Prison.
A great example of why the individuals breakdown into different ‘tribes’ to survive.
Here’s a funny thing to think about... well, not funny really.. but, if the United States (and most other countries) suddenly ceased to exist in it’s current form, let’s say due to a major, global disaster (Asteroid hitting the planet for example).. the world would be reduced quickly to small, surviving enclaves of humans who would effectively save themselves as best they could and most likely would NOT adopt something like “Federalism” and a Constitution to continue to exist.
In short, they’d kill anyone trying to take their survival benefits (food, land or whatever) and it would be... golly, tribalism. And they’d survive just fine without Congress wouldn’t they?