The UN has actually tried to address atrocities by the US, and as a result the UN isn't very popular with the sort of Americans that think the US has every righ

The UN has actually tried to address atrocities by the US, and as a result the UN isn't very popular with the sort of Americans that think the US has every right to commit those atrocities, but that has never had much chance because the US is too powerful and has veto power. So does Russia, which is why the UN is also not much use at stopping Russia, but Russia currently occupies a seat that's technically not theirs, so it can be taken away. But ideally, that veto power should never have been a thing.