the un is communist but conniving, every nation in that group is just in a power struggle with each other... think about it
I don't doubt their intentions I doubt their ability to make a power grab without freaking people out of complacency
also, as soon as the un got REAL power to do more than attempt to pull strings (usually just stirring up more conflict) and take over some countries outright, the members would all fight it out to get top dog status within the un
think about it, russia couldn't even keep the warsaw pact nations in check... because communism always goes back to fuedalism (king state actually has a king and king has fuedal lords and those lords have vassals, and they ALL want to stab each other in the back)
that's why I like capitalism, you don't have to kill or be killed, just work till you have enough money to be content, yeah some people are cutthroat about it but they have to spend all that money somewhere
and no I'm not wealthy, I barely make more than minimum wage (under 30K for sure, va disability checks and full-time plus overtime work)
long story short the un can't really take over the us, but it can screw this country up worse (then again the progressives did in the early 1900's and the backlash was able to straighten america back out for the most part)