The justification was the tremendous economic potential needed local, independent government given the constraints of communication and transport at the time. That's what they taught me in high school History, anyway. Also, that about 1/3 of colonists supported the revolution, 1/3 the crown, and 1/3 weren't aware it was going on.

By the way: I'm new here, and I notice there's no way to neutralvote once you've already voted. e.g. I voted you up and then changed my mind, but don't want to vote you down. So you get a freebie.