I have no great love of conservative politics, but there's a convincing argument to be made that their ideas and views are routinely suppressed by media outside of explicitly partisan media outlets (i.e. Fox News or talk radio). There are a number of studies that back up this claim. A 2008 study[0] found that 88% of journalists donate to the Democratic party. Jonathan Haidt has shown[1] that non-economics social scie…
This seems to be measured by "Democrat" vs. "Republican". An alternative hypothesis is that mainstream American political views have skewed strongly towards the right in recent decades, but that shift did not touch the academy, and also that America became more prominent in research in recent decades (so more researchers labeled themselves by American political parties).
Anecdotally, it seems like there's a liberal/conservative split within the Democratic party, exemplified by Sanders/Hillary. I wonder what you get if you figure out some good way to quantify that, and then redo the statistics.
This is only frightening if you think that there's a lot of ideological conformity within the label "Democrat", or that the specific ideologies with the label "Republican" need representation. There are probably good arguments for those, but they're not completely obvious.