A recent article in Slate describes the relative dearth of Republicans and relative abundance of Democrats amongst scientists within the United States. The basic thrust of the article is that this has resulted in scientific data being skewed in favor "Democrat issues" and Republicans being accused of scientific illiteracy when they express healthy skepticism.
The criticism that the political leanings of scientists may color their interpretations of data is a valid and important one. It is worth asking why there are relatively few Republicans working in science, as that question will tell us some important things about both politics and the place of science within society (and I am not pretending to know that the results of such an investigation would be) However, this article is an example of what happens when a writer attempts to tackle an issue without any understanding or comprehension of the issue's history. Just as one can not ignore the real, but often over-stated, role of the 60s radicals in shaping university life, one should also not ignore the history of the Republican party in figuring out the political life of academics.
Okay, first off, the author reports that only 6% of scientists polled are Republican, while 55% are Democrats. A big disparity, to be certain. However, there is no indication in the article as to whether or not this is a new thing. My own experience with older scientists is that, as the age goes up, there is more of a political mix, and the balance of Republican/Democrat/Neither tends to balance out - again, though, this is based on my experience and not on hard numbers, so take it with a grain of salt. What's more, when I speak with these folks, it is often brought up that many who are not Republicans currently were members of that party at an earlier point in their lives and careers. This is, of course, anecdotal, but it does suggest that the matter may be more complicated than some sort of left-wing grab for science, as the author of the article seems to imply. It suggests that maybe something has happened to the political parties that has led to a shift in the political affiliations of scientists, rather than the scientists themselves being a bunch of ideological liberals.
First off, let's get at a false dichotomy and some false labeling in which the author of the article is engaged. The author seems to believe that if someone is registered as a Democrat, that they are ideologically liberal, and that someone being registered as a Republican makes them ideologically conservative. This is not necessarily the case. The terms "liberal" and "conservative" have become synonymous in our current political discourse with "Democrat" and "Republican" despite the fact that the positions staked out by the party often have little to do with either a liberal or conservative philosophy and much to do with securing votes from particular sectors of society.
If one actually brushes aside the rhetoric and looks at the parties themselves, there are certainly differences, but the differences are not of the "hard right wing vs. hard left wing" variety, but rather are differences of rhetoric (usually overblown on both sides) and practical approach to problems (and this is fluid, the "socialist Obamacare Plan" is actually nearly identical to a health care plan offered by Republicans under Newt Gingrich) - most people identify with the more fiery rhetoric of their party with little attention to what the party actually does. Contrary to the frequent claims that the Democrats are "lefty loonie socialists" the reality is that most of the positions held by the modern Democratic Party would be considered conservative by the standards of most nations on the planet. While the Republican party has, in recent years, been drifting more and more to a "Christian conservative" party, it has largely been a moderate right party as compared with the conservative parties in most other countries.
Also, as the podcaster Bruce Carlson often points out, the platforms of the Republican and Democratic parties, and their constituents, haven't changed all that much in the last century (until the last few decades, more on that below), and yet they have gone back and forth as to which is considered conservative and which is considered liberal. So, I would argue that the conservative/liberal labels are largely meaningless when applied to the two major political parties.
This is relevant because I have known many scientists who are politically conservative. Most of them don't adhere to what is typically called "social conservative" ideologies (these are often, though not always, based on tradition rather than clear evaluation of evidence, and scientists by nature tend not to go for that), but many are economically conservative, or may see value in gradual rather than drastic social change (making them social conservatives by policy for pragmatic rather than ideological reasons). But none of the scientists that I know who meet this description are Republicans. Some are Libertarians, some belong to even smaller parties, some are even registered as Democrats (further eroding the Democrat/Liberal vs. Republican/Conservative notion), and some eschew political parties altogether. When I have spoken with them about why they aren't Republicans, I tend to hear the same thing - they are uncomfortable in the Republican party because of it's insistence in recent years on ideological adherence, the notion that one can not be a good Republican if one is not also a Christian, if one does not believe in an unregulated market, and so on. I have even spoken with many former Republicans who still believe in much of the party's platform (and, let's face it, there are some good ideas in there), but who have felt alienated by the way that the party has been developing over the last 15 to 20 years.
What has alienated scientists further, as well as professionals in the humanities, is the increasing identification between the Republican Party and the Religious Right. This began in the 60s, but could have switched sides in the 70s with Jimmy Carter (an openly Evangelical Christian) in office - if only it hadn't been for some issues that Oral Robert had with the I.R.S. - and began to accelerate in the 80s, with Reagan openly mouthing many of the Religious Right's views on science (making counter-scientific statements about evolution and environmental science, for example). And the increased compression of the Republican Party and the Religious Right has continued to the point that, as you may recall, during the previous presidential primaries it was asked in the Republican debates if the candidates were willing to deny evolution, a basic scientific principle.
A further issue for many scientists comes from one of the factors that makes the Republican party an effective political party: it's relative ideological adherence (in other words, were the Democrats more competent, they might be pushing away scientists). Now, don't misunderstand me, there are many Republicans who disagree with the party line on many issues (hell, nearly a third accept global warming), but the Republican party has been better than the Democrats at pushing a narrative and getting their membership to buy into it. Many people who disagree with the party's positions will stay with the party out of a desire to change it from within, or a desire to be part of a party even if the disagree with some of its points, or out of personal inertia or family tradition. Scientists, by the nature of people who become scientists, tend generally to not to fit these categories. They tend to be the sorts of people who question ideas and assumptions, and go where the data leads, because of they weren't they'd not have become scientists. The Republican party of old could easily accommodate such people, and the Democratic party does today (which, ironically, is one of the reasons that the Democrats have such a hard time doing targeted messages and winning elections). This increasing push for adherence (to the point that it is not uncommon to hear the official and de-facto Spokesmen for the Republican party demand that elected officials adhere to party positions on issue regardless of the data) alienates the sorts of people who are drawn to science.
The simple fact of the matter is that while there are few specifically Republican scientists, it is not all that uncommon to find scientists who do hold to the stated conservative ideals of smaller government, less intervention in peoples lives, and individual responsibility. It is probably true, because of the history of academics in the latter half of the 20th Century, that many academics are more likely to be truly left-leaning - though my own experience indicates that this is far more common in the humanities than in the sciences. But it is also true that saying "hmmm, few scientists are Republicans, therefore it must be the scientists, and not the political party, that is biased" makes little sense. It is worth noting that the author of the article never addresses actual scientific controversy, except in the most oblique way possible, and never addresses data. He focuses solely on the stated political affiliations of scientists in a poll, and hell, he doesn't even state anything about the methodology or margin of error in the poll! If one looks at the history of the Republican party over the last 30 years, it seems less likely that there has been a vast left-wing conspiracy to take over science than there has been a tendency for this political party to abandon scientists who would once have fit in.
Hell, it is telling that the Republican Party went from an organization that once respected science and scientists to one where prominent members in elected office can publicly call for the use of criminal prosecution in an attempt to bully scientists into silence. I have heard many attempts to justify this, but all of them fail when you actually examine the case. This was a simple case of someone in power trying to silence someone who doesn't fall into line.
The question isn't "why aren't more scientists Republicans?", but rather "why is the Republican party alienating scientists?"
The author of the article is right about one thing - there are political consequences to the perception of liberal bias in the sciences. He is wrong about something else, though - an increased awareness of scientific methods and principles amongst the general public would benefit the public, as people on the political right and left, Democrats and Republicans, would be better equipped to see when someone with an agenda is trying to pull the wool over their eyes, and would probably result in the Republican Party becoming a better party. Unfortunately, I have no idea how to get people who would deny science to support education in science.