E.G.

Certain weird statements recently made by Donald Trump have created renewed interest in the scenario where

America metastasizes: Each of the world's countries become states of the USA, one by one, until finally the whole world is under a world-encompassing government that is either continuous with or a descendent of the current American federal government.

I don't know whether it is likely for America to metastasize in this way, and I don't know whether we should try to make it happen.

I suppose the first thing to say is that the current world order is bad in a bunch of ways.

In the current world order, there's a few strong political entities (e.g., USA, EU, UK, China, Russia, a number of others) and then there's a large number of weak political entities. The strong ones share control; the weak ones have to submit to whatever the strong ones agree to amongst themselves.

If you are (i) a citizen of a strong entity that (ii) has a democratic government (in the weak sense that the government is responsive to its citizens' interests and desires) then that's great for you and you'll have a number of big advantages in life, relative to those who are not so fortunate. Many, perhaps most, of the people who live in territories controlled by internationally weak political entities either struggle just to have the bare minimum required for day-to-day survival, or simply do not have the bare minimum. And this is so, at least in significant part, because they live in a world controlled by strong foreign governments that are not responsive to their interests.

Also, even if (i) and (ii) hold for you, the current situation is not ideal for you. For one thing, you are not able to move about in the world as freely as you might if things were different. You're seen as, and treated as, a foreigner everywhere you go, except in your home country. And if you want to trade or do business with, or collaborate in any way with, people who are outside of your home country, you'll need to pay attention to at least two sets of laws and practices, etc.

The natural idea about how to improve this situation of power-imbalanced international fragmentation is to set up a completely new government that would have jurisdiction over the whole world. But this approach is unlikely to work. Any new world-spanning government that anyone tries to set up will always be immediately smothered by already-existing strong political entities who see the new government as a threat and competitor.

So, if one likes the idea of a one-world government, one should consider the idea that one of the already-existing strong political entities might take on the job via metastasis. And I suppose that all of the already-existing strong entities should be considered as candidates for that role, but the United States seems to have at least two distinctive features that might make it uniquely qualified, or so fans of this idea might argue.

First, unlike most of the other already-existing strong political entities, the USA has a mechanism for, and track record of, welcoming foreign territories as new states. And states of the USA, whether they are among the original 13 states or recent additions, seem generally to be treated as approximate equals of each of the other states. Granted, there are not-insignificant inequalities between American states (e.g., inequalities baked into the Electoral College system) but on the whole it seems that these interstate inequalities are less severe than the inequalities that exist between, e.g., Nebraska and Mozambique.

Second, the USA is already the closest thing in existence to a world-spanning government. The USA is today running a kind of empire in which countries outside of the empire's "home country" are subordinated in varying degrees, without being properly represented in the policy-making processes of the home country's government. A metastasizing America would basically be a reform of this already-existing empire, where presently subordinated countries would each, one by one, achieve the status of states of the empire's home country. By contrast, in order for the EU or UK or China or Russia to metastasize, the already-existing American empire would first need to be disassembled and defeated, which could be costly and bloody.

I suppose it is useful to distinguish two main questions. (1) Considered in itself, would America's metastasis be a good thing? Is a possible futureworld in which America has already metastasized likely to be better than the world we've presently got, or better than the world we're likely to end up with, etc.? (2) Even if the answer to (1) is yes, are the transition costs too high? How much danger, and how much injustice, would be involved in America's metastasis?