The "New World Order" if you will is already happening. Globalization is making the world a much smaller place. Even staunchly independent states like Switzerland are finding it hard to continue to be isolated from the world.
I think the great struggle of the 21st century will be between Americanism and the rise of the Chinese economy into a world power. In 20 or 30 years, they could have the worlds largest economy. That would raise a few eyebrows to say the least.
And with the growth of things like the WTO, the IMF, the World Court, etc,.....one world govt isn't a far fetched idea.