Of course there is. We've lived under centralized power for hundreds or thousands of years, after all. Why would The Powers That Be suddenly cease wanting to Be?
But centralized power cannot be justified, it can only be rationalized. If you think about the idea of the social contract for a moment, you should realize that it's not a contract at all, but merely a shackle for our minds, to keep us from finding a way out of the maze of our brainwashing.
For starters, you were never even asked, you never had a chance not to participate, and you can't just opt out of the system either. You're either inside a country, or you're freezing to death in Antarctica. It's not much of a choice, but a voluntary choice is necessary for any contract to be binding.
Read this: http://spot.colorado.edu/~huemer/book3.htm