I don’t think there is anything wrong with supporting the troops of allies. Supporting the troops of a hostile nation seems to tread rather close to treason (if there was an actual war it would be treason). But even with allies I think you should be specific about which troops you are supporting if they aren’t yours.
Trump, on the other hand hardly supports American troops.
I don’t think that a One World Government is remotely likely in my lifetime. And if there was one the US Constitution has some admirable parts - and some messy compromises. I wouldn’t like the latter to be replicated.