> For me the canary in the coal mine event was Gulf War 1 when the US went around asking other countries to help pay for our war.

On the contrary I would say Gulf War 1 was the last example of the US empire operating as designed: a large coalition of westernized nations implicitly following the leadership in the US, in a network of institutions and alliances entirely built around the assumption of US supremacy.

IMO the second Gulf War was the first blow to the US-centric international system... and it was the US themselves who dealt that blow.