The Constitution is an amazing document that, despite certain flaws (I'm looking at you, Three-fifths Compromise), created a lasting governmental system that wisely allowed for Amendments which could keep our nation intact as it grew in geography and population, and as times and technology changed. Although some weaker attempts preceded (I'm looking at you, Articles of Confederation), our Constitution stands as one of the first times that the powers, rights, and responsibilities of a people and their government were codified. It has become the model upon which other such documents have been built.
It's on days like today that I remember that America is a land built of disparate ideas and people who somehow manage to come together to make the greatest nation that the world has ever seen.