You're a smart guy. I don't know if you have *ever* posted something market-wise or trading-wise with which I have had an issue. But the most *complex* of trading/investments is still simple enough to be coded.
International Relations (no matter how realpolitik it may be when up close) is not simple. It is (to quote myself) "...long-lensed, involved, filled with subtleties and nuance, based [in] strategic thinking, clothed in solid principles.
The solution is Statecraft."
That is not a quick nor a simple answer, and so you get the last word to clang an objection. But the fact remains that the current path to isolationism denies the stabilizing influence we had amongst our enemies and our friends, and we now face a more-unstable world, populated by enemies who play us like a fiddle, and friends who have seen the severed ties and have taken their loyalties elsewhere. Ponder that -- it's a fucking disaster.
Isolationism throughout history, anywhere on the globe -- lessens the country that practices it. Without exception.
Defense is always more expensive.