The theory behind John Dean's Conservatives Without Conscience is that neo-conservatism has its roots in the phenomenon of Right-Wing Authoritarianism. Working from the studies of Robert Altemeyer and a handful of other social scientists, Dean states these authoritarians have taken control of the Republican party, and use appeals to social dominance in order to maintain power.
As I think I've said before, Conservatives without Conscience doesn't do a very good job of selling the research into authoritarianism to someone who's unaware of the social science that backs it up. This is partially because the author does rely so heavily on Altemeyer--my guess is that the book was written quite quickly, and so Dean only occassionally ventures out into other sources, like Adorno and Duckitt. You can get a slightly wider viewpoint from futurist Sara Robinson in her "Cracks in the Wall" posts at Orcinus (parts one, two, and three). She's also written a series of articles on talking to authoritarian followers that she calls "Tunnels and Bridges."
But having spent a few months thinking and reading about the rise of fundamentalism and evangelical Christianity in American politics, especially as part of the rural-urban gap, Dean didn't have to do much to convince me. Even just in the past year, a number of bizarre (at least to city-bound liberals to myself) stories about fundamentalism have popped up, particularly as election pressures became more intense:
A common thread of all these movements is their emphasis on submission: the children submit to the parents, the woman submits to the patriarch, the family submits to the church, and ultimately all submit to God. This "submissive" relationship is not just about power, although that is certainly a significant part of its appeal (I note, for example, that in youth evangelical movements the primary function seems to be giving privilege to men without forcing them to give up their... less responsible habits). These are basically movements that are intensely interested in heirarchy: both knowing your own place, and keeping others in theirs.
This explains, frankly, quite a lot.
Take one of the standard objections to evolution by fundamentalists: if Darwin is correct, they say, then we're no better than the animals. To many secular urbanites, this argument might sound genuinely puzzling. It doesn't take a vegan to recognize that yes, human beings have many things in common with animals. A person only has to look at a chimpanzee or a gorilla to see the many similarities. But to someone whose psychological makeup is geared toward negotiating a rigid power structure, the difference between humans and animals is not just an academic question. It's part of a defined relationship where one is dominant and the other is food. Muddling that heirarchy is not just a challenge to the supremacy of humans, but it unseats the fundamentalist's self-positioning. Who are we if we're not plainly better than apes? Although the youngest Karamazov's cries of "without God, all is permitted" are philosophically dubious, they still resonate, and it's not because they speak to atheism. It's because they speak to loneliness: without God to anchor a moral spectrum, all kinds of troubling grey areas begin to appear, and we basically have to solve them for ourselves.
The authoritarian angle also ties into theories I have about why conservative humor isn't funny, but they're probably a bit insulting.
Gay marriage, feminism, progressive taxation (leading to a more mobile class system)--perhaps the arguments over these issues are not really about rights after all. Maybe they're really about eliminating ambiguity. For people like Dean, religious extremists may have hijacked the party, but it seems to me like such reticence is really a part of any ideology calling itself "conservative." Eventually, authoritarians had to take the leadership at their word.