When I was in college, I took a course called “Race, Gender, and Science”. Someone might argue the very title implies a liberal curriculum. It was taught by the English department.
In the course, we read historical documents (such as Jefferson’s Notes from Virginia) and contemporary essays (we read chapters from Edward Said’s Orientalism, for instance) related to how science has defined and distorted race and gender, usually for the negative. I remember writing an essay about Stargate and how orientalistic thinking was apparent in the movie. I also wrote papers on environmental racism, the IMF and the World Bank, the perils of academic tracking, and the Tuskeegee Experiment. A lot of it was right up my alley and I enjoyed the class.
Now, a conservative could look at this curriculum and see that it was nothing but a “librul” studies class. He or she would probably wonder what was the point of students taking such a class, particularly since it was supposed to be only an English class, and we were all engineering and science majors. Additionally, the student body of my university was fairly conservative. One could argue that such a “liberal” class was not needed simply because of that.
However, it was an elective, not a required class. Courses in performance art, technical writing, sports writing (I kid you not), film, and public speaking were alternatives…and all of these were politically neutral.
I’d also argue that this Race, Gender, and Science class did not necessarily have to be “liberal” or “conservative”. Even conservatives have to admit that race and gender have played central parts in how science has been applied in our society. It is not liberal to discuss Jefferson’s views on race or to talk about how the media has played into gender stereotypes (only an idiot would deny that Jefferson was a racist-in-conflict and that the media is embedded with stereotypes). I think my course was fairly liberal (based on the assigned essays, which were definitely from a singular political bent), but it didn’t have to be.
Also, the course required that students participate in in-class and on-line discussion about the readings. Some of the most vocal students were the ones who did not agree with the point of whatever essay we were reading (for instance, I will never forget the guy who said people who live in toxic neighborhoods just need to pick up and move, despite the fact that the only neighborhoods these people can afford are typically the ones that are the most toxic). So we all had a chance to persuade and be persuaded. The professor’s political views were really never that apparent (even though she was probably of a “progressive” bent, based on the kinds of readings she selected for us to read).
Conservative profs in the humanities may be of some benefit, and I agree with the OP that it will take an AA-like policy to achieve this. But conservative profs aren’t really needed in the sciences, IMHO. I’ve encountered a bunch of conservative scientists. We don’t really need anymore. 