Does grad school make you liberal?

In short, no, liberals are just more likely to select themselves into grad school attendance (PDF). The abstract:

This paper analyzes longitudinal data to evaluate three claims that are key to a recently developed theory of professorial politics. The theory explains the liberalism of the American professoriate as a function of reputation-based self-selection: because academia has a reputation for liberalism, liberals are more likely to pursue graduate degrees and academic careers. We examine whether in fact young Americans who identify as liberal are more likely to enroll in graduate programs with the intention of completing a doctorate; the proposition that such a tendency cannot be explained away by variables unrelated to occupational reputation; and the claim, also made by the theory, that exposure to many years of higher education is not a major cause of the liberalism of graduate students. We find support for all three claims, with ambiguity only on the question of whether the greater propensity of those on the left to attend graduate school results from personality differences.

Within the particular fields I'm studying this is even more true. For public policy -- speaking very broadly -- if you're conservative and mostly want to cut government then why study how to do government better? Why not study business or law instead? And public health has traditionally been a field that  favors a lot of government intervention too.