Given the course we're going now, the reality is that we will become one world government. I welcome that day, even though I'll never live to see it.
If you've paid close attention to history, you'd notice that capitalism, and all its bastard forms, is tending to win out over other forms of economics. Why is this important? Because we are exporting our culture in a mass market fashion. With the advent of radio, television, and the internet, technology will soon overcome communication barriers that existed since human inception. In the society of the future, there won't really be any reason for borders, tariffs, or skirmishes. You can try to protect American workers and products by any number of tariffs you like, but in the end, capitalism will find a way.
We already see it happening. Labor is being outsourced overseas from American companies at ridiculous levels. You do the math...an American corporation can pay a unionized American worker about $30/hour for his services (including appropriate federal and local employment taxes) or can outsource the same work to a foreigner (perhaps over the internet) for about $3/hour for the same job. Ethical dilemmas aside, it's not a tough decision to make, and several companies are making the plunge.
Like it or not, it will happen, assuming we don't annihilate ourselves in some fashion before it does
Progress will force us to evolve.
Then again, I may just one of those crazy people that believe our cultural differences are dwarfed by the sheer fact that we are all homo sapien. That, in itself, in the grand scheme of things, makes us all kin.