The evidence is the very words those on both sides of the dividing line utter. Even more, the evidence presented by the actions of those in positions of leadership versus the common people of this nation, (those "We the People" who are supposedly the final arbiter of what this nation is) shows that the divisions aren't just red/blue, but power/people, individual freedoms/regulation, and personal liberty/imposed behavior as well.
I'm currently reading "1776", the new book by David McCullough about the American revolution. Much of what I'm reading could be very easily rewritten to be contemporary, merely by substituting the US government (more the Democrats than the Republicans, but many of the latter are hypocrites and control freaks, too) as King George and the English nobility, and center-right blogs (both their authors and the majority of those commenting on them) as the American people. The MSM is on the side of the King, along with unions, many non-government organizations, and the entire left side of the political spectrum. Religion appears to be the new "Stamp Act".
Of course, not everything is identical. There's no precedent for the boorish, antagonistic, moronic and haughty behavior of people like Jimmy Carter and Bill Clinton, Dianne Feinstein and Charles Schumer, or people like Cindy Sheehan, Ray Nagin, Jesse Jackson and Louis Farrakhan. The total absurdity of the continued debate about whether we should be fighting a war against people who have attacked us is just one bit of the evidence that we're engaged in an internal war as well. Newspapers and television used to have pretty much a lock on what Americans learned. That's no longer true, but they continue to act as if it is. Their lies, distortions, and exaggerations are continually exposed for what they are, yet their behavior doesn't change. They don't care to be truthful, just to be "effective" in molding public opinion about the subject at hand.
As with the American Revolution, the "King" may be currently in control, but the end is in serious doubt. Between blogs, world events, the rebirth of American individualism (the tsunami response effort, the Minutemen border patrol, the response to Katrina), greater access to information by more and more Americans, the difference between what the MSM reports and what Americans can see with their own eyes and hear with their own ears, and the greater and greater disparity between what the Left says they believe in and what they do, the American people are once more deciding they'll govern themselves. There are still many battles to be fought, but I'm beginning to be encouraged by the response of ordinary people, and the differences between what PEOPLE do and what governments and "agencies" do.
New Orleans, I think, has become the "Bunker Hill" of the new revolution. It's highlighted the inability of "government" to do everything, and that the best, most efficient means of responding is for people to help people - one-on-one, in small groups, and in voluntary alliances such as the Blogswarm for relief. Barriers are breaking down - not the breach of the levees in New Orleans, but the barriers between north and south, east and west, even red/blue, as well as haves/have-nots, Republicans/Democrats, and even black/Hispanic/white/red/brown/yellow.
People appreciate a helping hand in times of trouble, regardless of its color, race, religion, culture, or ethnicity. We see it in New Orleans, we see it in Afghanistan, and we see it in Iraq. Now we need to see it in the rest of the United States. What we don't need to see any more of is the language of divisiveness, of racism, of elitism, or power politics.