The USA, as a UN member, agreed to abide by the UN charter along with all the other UN members.
We can also leave when we feel it's no longer suiting our needs. Like, since its inception. (before, really) Also, the UN has changed since it was created. Back then, it was our puppet (for the most part). Now it's not, and is trying to be the overlord of the world and tell us all what to do. To that I say, we are Americans, and we will be ruled by no one. No more support, get the hell out of my country, and take a very long walk of a short pier into the trash heap of history where it belongs.
And the US is subject to the Laws of War just like every other nation on the planet (there was a reason why Bush cancelled his trip to Switzerland- he faced possible arrest)
What does that have to do with anything? (And by the way, I seriously doubt Switzerland or any other country would arrest our President. Our DOJ under Obama hasn't even tried that one. A, they'd hafta get past all the security, and B, do you really think they would they want the full wrath of the US raining down upon them? Go ask Japan how well that turns out.) Oh, and not every country is subject to the laws of war. Just the stupid ones who signed the treaty that limits what you can and can't do, and can and can't use. That's a joke. The whole point of war is to kill people and break things until your enemy loses the will and ability to fight back. Now we gotta tip-toe our way through wars and that drags things out. Just level 'em and be done with it.
Just like every other uneducated UN-hater you are ignorant of how it functions or what it even is.
Mmm, you like calling names, don't you? (I guess you still haven't learned that lesson yet.) I know exactly how it functions and what is done. Billions of dollars and tons of food and medical supplies (from wealthy the member nations, as a form of wealth redistribution) get sent to third-world dictators to prop them and their militaries up, while their people suffer and starve. Then when one goes too far, after hundreds of non-binding, limp-wristed 'threats' of possible action at some future, undetermined date if you don't stop after hundreds more non-binding, limp-wristed 'threats' of possible action at some future, undetermined date, either we (the US) go in, or if the UN blue-hats do go in, it's not good. They do all the atrocities our troops get blamed for. The only time the UN is strong on something is in regard to Israel. It's a place for anti-Semites to gather, bad-mouth Israel, and call for their punishment for just defending themselves. The only reason nothing ever happens is because we stand up to all the non-sense. You've also got countries with atrocious human rights records on the Human Rights Council (or whatever it is, a joke is what it is). On top of that, the whole (public) point of the UN, and its equally ineffective League of Nations predecessor, was to give counties a place to talk, to prevent more wars. How's that working out? But to those who know, the LN and UN were made precisely to create one world government so people who think they know better can tell all us little people what to do and how to live our lives. Progessivism 101.