The ability of the US government to bend other governments in a certain direction, is like a leak in and of itself, as I surely did not expect so many governments, including mine in germany, to be this intimidated by the US powerhouse.
The US is intimidating. It has made all non-democratic forms of government illegitimate by waging wars of extermination against them, it is a quarter of the world economy by itself, its military black budget is almost certainly larger than anyone else's open budget and its open budget is greater than the rest of the world's military budget summed.
The US is the global hegemon. Russia, China and maybe Iran are independent of it. The US does not truly view the rest of the world as sovereigns but as subjects.
Curious, then, how many Chinese and Russians there are yet. Is the US inefficient, or are you reaching a bit? And the US can be disgustingly good buddies with non-democratic governments: the Greek and Argentine juntas, various Middle Eastern states.
What about all of the dictatorships that the US created or propped up? Saudi Arabia, Iran pre revolution, Panama under Noriega, etc?
The key is legitimate. Are there any dictatorships that don't even make a nod towards the idea of popular sovereignty? Any states where someone could say "L'etat, cest moi."?
As far as Panama goes, the US's Warsaw Pact.
I agree with a lot of your post, but it wasn't anything the US government did that made all non-democratic forms of government illegitimate. They have all been illegitimate since the very first time a gang of stronger men beat and killed a weaker one just because they could.
Neither might nor popularity makes right.