I just watched a very interesting TED talk by Paddy Ashdown about the shifts of power going on in the world today. He made several points:
A) Power is moving vertically, from the nation-state to the global community. With how interconnected everything is today, international governance will become increasingly important. Per him, this will probably not happen through the establishment, or strengthening, of an international government. Instead, this will be governance enforced by international treaties--something we are already seeing.
B) Power is moving horizontally, away from the West and the USA, toward the entire world. The West will no longer be clearly dominant, as other parts of the world rise in power, wealth and technology. The USA will probably remain the pre-eminent power for a while yet, but it will be the first among many, rather than the only kid in the park.
C) Power is moving away from military strength, and into other areas: industry, technology, infrastructure and social clout. The world is so interconnected now, no nation-state can crouch, self-sufficient, behind their walls, because no one is self-sufficient behind their walls. Riots and grain shortages on one continent can have consequences across the world.
We must understand that we have a shared destiny, with each other, and with our enemies.