<<We can either rejoin a UN that is even more corrupt than it is today, or we can start hammering the UN, root out the corruption and expose it for everyone to see, and put them in jail.
No reason we can’t do both. Withdraw from the UN *and* prosecute them all for misappropriation of funds, etc...
A non-member state prosecuting members... Yep, that'll work out. Of course, once you start running the members through the prosecution mill and expose billions skimmed off into private accounts, you might find a whole lot of support to just flush the whole thing down the drain, so you'd get exactly what you're seeking.