> It's still very fucked up that the US signed a treaty with Iran saying "we'll lift sanctions if you do X", Iran did X... and the first thing the US did after the next administration change was to say "Fuck the treaty we signed, we're putting sanctions back".

Yeah it is fucked up. What is the word of the US worth if it's going to flip flop every time the party in power switches. That's going to have ramifications.

> Also, I don't see how the US has any sort of moral legitimacy to unilaterally decide which country is a "good actor" and which country is a "bad actor", even against the wishes of its allies (including western democraties). In a fair process the US would only be one of several countries deciding together, and would only act with common backing.

Every country can decide for themselves who are good and bad countries, and they're free to take whatever action they feel is appropriate, including war. That's how nations work. Now some actions have consequences, and some nations have more or less power and influence. The US does have some moral authority in that it sometimes stands up for what's right rather than what's in their best interests. For example, bans on buying conflict minerals.

The UN is supposed to function like you're saying, but in reality it's quite dysfunctional. Because of the veto system the default action is no action so it's hard to agree on anything.

> But don't act surprised when other countries start banding against US hegemony.

They can and they will, but such is the nature of things. Nations rise and fall.