Because the UN was create at the behest of the US, and thus the US has universal veto power. Simply, if the US doesn't want it, it doesn't happen. And yknow, we get off on war.

It did. Sort of.. We still have wars of terror. drugs. waste etc, which arent wars. The non wars we have where people are shooting and dying are Police actions, special military operations and counter insurgency strikes..😷

Because the UN is useless nuisance.