David Brooks wrote an interesting book on this called Paradise Drive, but the focus there was a bit different. In a nutshell, right of center people choose to live in lower density and left of center folks choose to live in higher density. Why?
1. Children–More children equals more conservative. There are so many available data to support this idea that I will leave the cites up to the reader (as again I lack the time). The most liberal women are the least fecund, conservatives are the most. When you have a child (or especially more than one) city living is difficult and annoying. Even without children, married couples, who don't need to go to bars etc are likely to live in the burbs. This is the most obvious reason, but there are subtler ones.
2. Religion–This directly relates to point #1 (religious are much more fertile), but I think there is a more nuanced ancillary reason. I have no children and I prefer lower density. In the Jeffersonian sense religious people like some kind of nature, rather than the paean to man that cities are. Second, Christians in particular, which obviously make up the vast majority of religious in the US, at least partly desire to remove themselves from pagan culture. That is easier in the suburbs where you can be alone. The more dense, the more you are constantly exposed to any number of objectionable sights and sounds etc. As strange and silly as this may sound, I think it is a powerful motivator.
3. Taste Culture–Liberals, yuppies, activists, these are all taste culture people. This often coincides with religion. If you worship created, rather than Creator, you are likely in this 'taste culture' idea. Don't get me wrong, I don't think there is anything wrong with it per se, but I think it can be related to the worship thing. What do I mean? Well, religious folks might draw their friends from church or school or scouts etc. Yuppies et al tend to derive friends from taste culture. They are 'foodies' or hikers, or insert social category here. High density living caters to this more simply because there are more opportunities for interaction and specialization.
4. Legal–This is a catch all category but perhaps the most profound. Firstly that the zoning laws of cities (along with higher density) make property more expensive. Therefore families move to the suburbs. But it is more complicated. Taxes are often lower in the suburbs, which is obviously a concern of conservatives (b/c you know, we are honest and actually pay our taxes, unlike Dem pols). It is also often easier to do what you like with your property in the suburbs, though with neighborhood covenants this is increasingly less true. The big one is of course that the draconian gun laws of cities drive conservatives out.
About 80% of the country according to the census is urban. Obviously, this does not mean urban urban, but rather developed vs. rural. There are those who believe that culture emanates like a radio wave out of the cities, and there is some truth to that. But I believe one of the reasons the U.S. is still tolerable compared to some other Western societies is that we have allowed for semi-urban development, without the problems and pitfalls. We need to encourage this. The lefties decry this as 'sprawl' and there is something to that argument that we can't ignore. Some suburban spaces are ugly, wasteful and dehumanizing. But hello! So are a lot of very high density urban spaces! What we need to is develop sensibly for a variety of needs. If we let the left command suburban policy to make it more dense, we will lose these spaces and the heart of America.
There is a lot more to talk about here so feel free to chime in. Next I will deal with the future, and how I think these categories are going to become even more difficult as I believe we are on the cusp of a transport revolution along the lines of the auto 100 years ago.