And no one has the power to stop it either. The most that fanatic nationalists or racial supremacists can do is slow things down and make life more miserable for those around them.
The smallest independent collection of humans used to be a clan or band, a group of 20 or so related folks. In prehistoric times, a nuclear family could not survive alone. You needed at least 3 or 4 hunters, 5 to 10 gatherers, and enough hands to share the work and enough heads to maintain the group's knowledge.
Nowadays, a nuclear family appears on the surface to be self-sufficient, yet they can't build a house and distill gasoline and carve up a cow. Even the mythic American pioneer didn't dig up ore and saltpeter and fashion a gun and manufacture bullets and powder. To survive nowadays, modern humans require a minimum group the size of a small city to harvest natural resources (grow food and trees, mine and smelt ores), deliver them to fellow brothers and sisters (build highways and trucks and stores, create capitalism which requires a trusted money supply), and manage problems between citizens (laws, courts, police).
The independent clans of prehistory eventually coagulated together into tribes and hordes. Perhaps this was done peacefully in a few instances, but most of the consolidation occurred through battle. And generally, the larger group wins. So it became pretty much impossible for a small clan in an area undergoing transition to the next grouping level to remain independent. About the only choice (if there was one) was which tribe to make an alliance with and eventually be subsumed into.
With the invention of agriculture, towns formed. They fortified themselves to guard against thieving nomads, and because agriculture is such an evolutionary advantage, the towns grew into large city-states who warred with each other after the nomads disappeared. Eventually, these city-states grew together into nations as the economy got more complex. Exotic minerals and spices had to be gathered from farther away which required easier trading, and more people had to be managed in larger armies. The cities quit having armies and worried about roads and sewers.
The next step was to form continental groups of nations. Many people think this step is just beginning with the European Economic Union, but it actually began with America which was (and theoretically still is) a federation of independent States (tiny nations as in Europe). The only other "nations" which have reached this level are China and the former USSR (currently stepping backward), which is also a main reason those three are world powers. In politics (war), bigger usually wins.
All three nations stretch across most of a continent. The next step is a world government. It is an inexorable result of historical trends. We can delay it, make it messy, kill lots of people (and we can do this with forethought or just through innate fear and natural stupidity), but we cannot stop the forces of history.
The best thing we can do is try to figure out how to make a decent world government, one that doesn't trample the rights of citizens. Don't worry about the rights of nations, because no government should have rights, just people.