Shit happens. Shit is always happening. Sometimes slow, sometimes fast, sometimes big and sometimes small.
For nations, that can be war, plague, natural disasters, failing infrastructure, whatever.
History has shown that with strong institutions, and civic systems, nations cushion the blow. Grain silos, transportation, military, all provide resilient systems.
Corrupt nations that lack these things fall apart, and can't handle the stuff that covers their way.
This is not a deep insight.