The UN is an impotent organization and can only hamper any future military actions that the United States might have to take to protect our own(and the worlds) security.
As long as we are a permanent, veto-wielding member of the UNSC, the UN can do nothing to hamper us. They have no authority over us unless we give it to them. As a standing organization, there are times when the UN can be useful to us, but the beauty of the current charter is that the USA can stop cold any action we don't like--we'll never get that type of power again in any new organization or if the UN is "reformed" by the internationalists.
With what we "contribute" to that den of thieves directly and indirectly, we can start stockpiling cruise missiles, smart bombs, fuel-air bombs, bunker busters and delivery systems which we will eventually have to use against our ostensibly "friendly" Euroeunuch allies.