Isn't that precisely the problem? The US (and to a lesser extent, Europe) attempts to justify its position and actions in the world on the basis of morality (spreading democracy, civilization, etc.), its opponents disagree and labels the US (and Europe) as imperialist beneficiaries, thereby creating a moral conundrum in which both sides believe themselves to be righteous, wherein might is the only answer.
Morality is thus cast as realpolitik's magic trick. Of course, that's just another way of saying that historically, no people ever believed themselves to be immoral - but then what's the point of discussing morality with regards to foreign policy?
Maybe I'm misunderstanding you here.
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Well, it depends on the system that is implemented.
If one can get a "moral government" (of the world, presumably), then that is not a subjectively moral government, but an objectively moral one.
Just projecting the given government onto another peoples would be just playing lip-service, without actually being a moral government.
Bear in mind that there needs to be voluntary adoption of the government policies; Liberia, for example, has an identical constitution to the USA and it is a markedly less fair society (warlords with Oxbridge / Ivy League PH.Ds leading armies of children in run-and-gun battles to control the countries rich resources, whilst the civilian populations are raped and tortured and driven from one refuge to the next).