First the Purely Geographic:
1. Exposure Theory–Lefties often argue that when you are urban you encounter people unlike you more often and this leads you to an enlightened 'progressive' worldview.' Clearly the bias in this theory clouds its reasoning. But if more finely tuned there is something to it. Urban people are more likely to be moral morons because they are over exposed to sinful humanity and therefore become desensitized to it.
2. Jeffersonia–The sort of converse is the country Jefferson hoped to create as a founding father. He believed that the yeoman farmer learned the best values from a) reaping rewards from his own hard work, and b) immersing himself in God's wholesome creation. There is clearly something to this. Exposure to nature shapes your character, and generally in a direction toward 'conservative' values. Please note that most lefty 'nature lovers' are urban yuppie folks who shop at REI and like to go to rural places while looking down on the inhabitants, or hippie 'activist' people who are also actually urban and like to go to rural places and imagine that all of the people there are poor and desperately waiting to be radicalized.
3. Urban Dependency–Urban dwellers are dependent on the government. Also a sort of yang to Jeffersonian yin, this theory is that urbanites are unable (and unwilling–see Katrina) to take care of themselves. When and if economic collapse happens these folks will riot and become brutally violent. Rural people will tighten their belts and survive. Suburbanites will do a mix of the two depending on how suburban they are and what city they surround (i.e. can they have guns).
4. Firearms–Which brings me to the last point. Guns are loud and dangerous and tend to be more difficult to safely use in urban areas. For this reason, folks who live in less dense places are more likely to learn how to hunt and or defend themselves. Isn't this you ask rolled into the other categories though? Well, yes, but I place it as a stand alone because guns are a pivotal political issue. No Democrat campaigns on a platform of 'you are a dependent urbanite who needs government and is so overexposed to sinful behavior that you have mistaken tolerance for depravity.' But they do campaign on 'we need to take guns out of the hands of scary people.'
This post is already well over the 1timmy4 word limit, but I will briefly close on the geographic reasons. Most folks vote on one or two issues, if they vote on issues at all (rather than say, 'hey that guy is black and doesn't scare me!'). But, their general political makeup is a complicated mix of surroundings, worldview and influence. These geographic categories are clearly powerful, and pervasive. Sure there are folks in urban areas that are conservative (me, though I wish I lived in a rural one–there are old school urban conservatives who will remain so), but they are clearly the minority. Our country is likely to progress mostly in the direction of urban. However, the density we do this at will likely affect our political character. The things I have mentioned all kind of have a geography influences political affiliation assumption though. Next post I will explore the idea that maybe it is also the other way around. Then, I will explore the religious dimension of these. Please feel free to chime in!