Who could have stopped a sovereign State like China developing nuclear weapons??
If you think anyone could, good luck to you!
And just who are the "goodies" as you say? The western democracies?? If so, what is your basis for saying that everyone other than the western democracies are baddies????
What is your analogy with cops?? The USofA has been trying to be the world's policeman since WW2 - they are technically bankrupt; their once world-renowned infrastructure has decayed so much that in places it is no better than some third world countries! In fact there are places where raw sewage flows into the streets. You really think this is what the Founding Fathers (may they all RIP) had in mind??
Just who are you kidding? Yourself???