The Sarcity of Conservative Academics

The term "conservative academic" is a bit of an oxymoron, but it's also an accurate description of myself.  I'm a 4th year Ph.D. student who regularly (although not exclusively) votes for Republicans.  Universities - especially secular ones like mine - are overwhelmingly dominated by those on the political left.  The chart on the right shows a break-down of various professions by political self-identification based on data from Dr. Neil Gross, a sociologist at the University of British Columbia.  Interestingly, professors are over three times more likely than the general public to self-identify as liberal but only half as likely to self-identify as conservative.  My guess is that on my campus the breakdown of liberal/moderate/conservative is more like 55/35/10.

Those on the left see this as evidence smart people are liberal and stupid people are conservative, while those on the right see this as an insidious liberal plot to subvert America's youth.  Even though I'm conservative I generally don't like the liberal bias argument, which equates to saying that somehow the lack of conservatives is analogous to the lack of female physics professors or the relative high school drop-out rates of ethnic minorities compared to whites.  Basically, I have never seen an case where an individual's political views were ever considered in admissions to either undergrad or grad school, course grades, or hiring in academia

Take the case of women in physics - it's clearly not that physicists are sexist pigs trying to bar the doors against women, but somehow 50% of the general population only produces 6% of the tenured physics faculty at American universities.  An article in yesterday's New York Times has me thinking that maybe there is something a little more subtle at work in both cases.  As Dr. Jonathan Haidt, a social psychologist stated in the article

“Anywhere in the world that social psychologists see women or minorities underrepresented by a factor of two or three, our minds jump to discrimination as the explanation. But when we find out that conservatives are underrepresented among us by a factor of more than 100, suddenly everyone finds it quite easy to generate alternate explanations.”

In physics conservatives aren't underrepresented by a factor of 100, but one study did find that there are 4.2 registered democrats for every registered republican among the University of California system’s physics faculty.  For comparison, sociology, ethnic studies, and performing arts all have ratios over 16:1.  The only departments with more republicans than democrats were general business, finance, and military science.  Physics is about on par with communications, medicine, and law.

So the big question is why.  Here are four possible explanations:

1. There exists overt bias against those with conservative views in academia - something like "liberals are smarter than conservatives".
2. Academics are subtly “politicalist”, meaning while they don't consciously use political affiliation to make hiring or admissions decisions, they do associate the viewpoints held by conservatives with a lack of intelligence or creativity.  
3. Conservatives are steered away from even trying to become academics because they think that “politicism” exists in academia.  
4. Conservatives are steered away from academia by other correlated factors like marriage and children that make it difficult to spend 9+ years in post-secondary schooling. 

In my experience I have seen all four of these things impact the careers of graduate students, although I would say that #1 is fairly rare.  I'm interested in what you think.  Have you ever run into overt "politicism"?  Is this even really an issue?