> The US navy defends pretty much any ship on the open sea to the best of their ability, no matter who you are flagged as

Unless that ship is headed to the Gaza Strip: see https://en.wikipedia.org/wiki/Gaza_flotilla_raid .

Peter Zeihan predicted that the US will gradually withdraw from being the global security guarantor as it doesn’t serve their interests anymore, and that we will see an increase in attacks on cargo ships on the open ocean.

For context, Zeihan is former Stratfor, the Zero Hedge of geopolitics.

I'm anticipating India growing their navy.

Attacks on cargo ships don't happen in the middle of the ocean (for obvious reasons) but near coasts, were regional powers can provide security.

Regional powers will provide security only if its in their interests to provide security.

I think the presumption is that the U.S. would (have to) respond differently to an attack on a U.S.-flagged vessel compared to an attack on anyone else. So, not a question of defense, but of the proportionality of the post hoc response.

They wouldn't save much US money. Longer routes means less shipping capacity, means higher shipping cost. That doesn't just affect europe, it's a market, a ship leaving China can equally go to Europe or the US. It affects the countries that are importing the most, at the very top of which sits the US.

Presumably most ships owners would look and discover that the US navy is the largest in the world and thus switch their flags to the US - they would then pay taxes to the US (and have to deal with a lot of other US laws that they don't now). Either that or they would pay a lot more insurance. Ships going to Europe might switch to either UK or France for flags (again paying respective taxes and laws) - both are reasonably powerful in their area, though not on US level. China's navy is up and coming and so may be worth looking at for a flag as well.

Note that the budget of the country in question is what is really being talked about, and not the entire GDP of the country. It is possible for the US navy to save money while costing the average US citizen money.

>Presumably most ships owners would look and discover that the US navy is the largest in the world and thus switch their flags to the US - they would then pay taxes to the US (and have to deal with a lot of other US laws that they don't now). Either that or they would pay a lot more insurance.

You've just described mercantillism. Post Bretton-Woods is the first time in centuries the world hasn't worked that way. The dream of free trade and globalism was that everyone had equal protection on the seas. I fear you're correct that we're returning to a darker time where autarky reigns and trade is restricted to essentials.

Oh, the post-Pax Americana world situation is going to be a lot darker than that. Multilateral nuclear proliferation, here we come!

If only there were a body of water through which the ships could sail from China directly to the US...