Should the US Rethink Involvement with NATO and the UN?

The UN is a moral wasteland—how could it not be, given that it is partially composed of many thuggish regimes? It might be time for the United States to leave the UN. NATO, on the other hand, is a more complex situation that has become increasingly complicated since we won the Cold War. Was it necessary to continue expanding NATO—provoking Russia—when we could have focused on bringing Russia closer to the West?