Well, it was started via the initiation of force. Which is one of only two sins in libertarianism, so if someone is a consistent libertarian they can't advocate for that as the way to get going.
The revolution came about first, but the United States government was enacted by a vote of the second continental congress, formed of delegates from the thirteen colonies.
What I'm getting at is that the rulers of the new government voted to start it. That's pretty much what I'd expect from any government.