ArthurTandy1 wrote:Nonsense. During the Cold War, the UN never stopped the Soviets from doing anything they wanted to do. They invaded Hungary and Czechoslovakia and Afghanistan. They gave arms and aid to Syria's dictator and supplied the Arabs with arms so they could attack Israel. They placed missiles in Cuba and supported the North Vietnamese in attacking the South. The UN never stopped North Korea from getting nuclear weapons. They allowed India and Pakistan to get nukes and threaten each other. Despite their UN membership, India and Pakistan have been at war since 1948. The UN has done nothing about world wide terrorism by Iran and the Taliban.
UN doesn't have an army to stop anyone. But it can shift opinion and provides control through the UN security council. US and its allies have 3 UN security council seats. UN in general is a massively beneficial tool for the US overall considering the number of its allies and block voting if that is needed in other institutions within the UN.
Long story short, if US leaves the UN then it will not only loose those tools but also loose almost any diplomatic control it has over China, Russia and several other countries like Iran and Korea.
It is a complicated subject though, since the UN was designed to be ineffective against the security council members by the creators of the UN. (Mostly US but USSR agreed to this system after some time so they can be blamed also.) The reason was simple, because if UN had control over USSR or US policy then they would never join the UN in the first place.