And how do you suggest they do that?
The only thing which counts is raw power and the means to deliver it. The US just got a lesson in its limits from the Iranian regime.
Countries with natural resources need their own defense against thieves like the US and its vassals. Libya, Iraq, Syria. Oil and no nukes. Fat use the UN was for them.
(Forget about the UN. Take a home owners' association. In due course a clique will take it over and corrupt it.)
And advocating for the dissolution and replacement of the UN due to it being ineffective is deeply ironic, because that's exactly what happened with the League of Nations, which led to the later formation of the UN.
You seem to be in an argumentative mood, but nothing I said is disagreeing with you about the ineffectuality of the UN.