That it establishes a nation whose government is a government based on law, a republic. That is what preserves individual liberty.
This is an excellent video clip explaining different forms of government. I learned more about that topic in the 10 minutes it takes to watch than all I was taught in public schools. It’s very concise.
Different forms of government
http://www.youtube.com/watch?v=DioQooFIcgE
Yep, I’ve seen it. It is excellent. I stress individual liberty when talking to other people about the specialness of the American Constitution.
That is American laws are valuable only in as much as they work to preserve individual liberty.
That’s why I also stress the General Welfare Clause.