We call ourselves the "united states" Why then...

250 million people spread over a huge country with very different backgrounds and cultures. Even though the states are united the differences are too great to agree on everything :-)

Well said, little! It's not just the politicians that sling mud at one another, but that is a perfect example. We are not united anymore because we have become a society that values our own personal "rights" too much and don't care anymore about anyone around us. We need to move back toward doing things for the good of all.