See, here's what I think: I believe that every nation has a right to have its people be the be dominant group within society, whether demographically, culturally, politically or whatever. This is equally true for Egypt, France, Jamaica and Thailand, and in fact every nation and every culture. So basically, nationalism for everyone. So if it gets to the point where, say, Muslims make up 20% of the population of France and refuse to assimilate, I think France would be perfectly justified in closing down the borders and forcing assimilation. But the opposite is just as true. If Frencmen start moving en masse of the Middle East, I expect the local governments to to everything in their power to preserve the heritage of that nation. Given that a nation as coherent unit is defined primarily by its culture, history, religion, race and so on, once those factors stop being more or less uniform the nations ceases to exist.
It's about money, nothing else. People from poor countries move to rich countries. Which is why I maintain that the best way to preserve a country's dominant culture/race/religion is to have it be poor enough that no one is going to move there. Which means most of the world is in the clear, for now, and the West, on account of being rich, has a potential problem on its hands. But like I said earlier, the point at which you should seriously start worrying is a ways off.
