As long as the UN exists, the USA has to remain involved and flexing our muscle from within.
It sounds resolute to say "get the UN out of the USA and the USA out of the UN', however, that corrupt group of grifters would have more power, not less by our absence.
The void we leave would be filled with Putin, Chirac and Schroeder. Can we afford that?
Otherwise, I share your sentiments.
Without the US the UN is done!
The French, Russians and the Germans can't afford their own governments, let alone the UN. Start cutting the funding and watch it collapse!