There are plenty of people who model this out. It would consist first of a perio

There are plenty of people who model this out.
It would consist first of a period of wars to settle long standing territorial disputes, and long standing resource disputes.
Next it would collapse the world system of trade and force more countries into local trade and autarky.
Many modern countries would face starvation rapidly and the capacity to starve out opponents would be a strategic utility.
Many modern tools, equipment, and technology are produced by a combination of twenty countries and a ridiculous number of naval crossings.
Piracy would return and as a consequence territorial and trade route capture would be militarily advantageous.
If you’re switzerland or the USA you’re in pretty good shape. Otherwise, you aren’t.
And this is just an outline.

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