There is absolutely a cultural divide in the United States today, in my opinion. I believe that the most important cultural divide is between (generally speaking) the coasts and the interior or perhaps the big cities and the rest of the country. Of course, there are people in each of these places who don't fit in, but it is a useful shorthand.
The divide is between people who are more traditional culturally and those who are not. The first group tends to be from the interior and tends to be somewhat less educated. These are the people who make up the "red states" and can be found supporting the Tea Party.
On the opposite side is a culture that rejects many aspects of tradition -- it is a more skeptical and perhaps intellectual culture. This is a culture that, for example, does not really believe in the outward and traditional manifestations of faith and patriotism that are common to the other culture.
(Generalization and perhaps overstatement alert here...) To the coastal elites, the traditional people seem like a bunch of ignorant rednecks. They do not think enough and blindly follow tradition or their gut instincts. To the traditional people, the coastal elites are not really American. They do not think in traditional American ways about things like the flag and God. They seem to shy away from things that seem like common sense -- they rely on sophisticated ideas instead of on traditional common sense.
Again, this is overstated and overgeneralized, but I believe that this divide exists.