> Under Trump the US has voluntarily relinquished that role

I would argue the process was started under Obama, and continued under Trump and Biden. What caused that shift is an interesting question in itself. My theory is that once Obama won on the platform of limiting US foreign involvement, the writing was on the wall and the politicians after him all became isolationist as that seemed to win elections.

The difference is that Trump, an incompetent populist he is, doubled down on the process so much that it became a very conspicuous mess.

I suspect we'd be living in a completely different world if John McCain was elected in 2008.