How bad is the ideological diversity problem on campus?

This bad, at least at Ivy League bastion Cornell. where The College Fix found that a grand total of just 17 registered  Republicans (a stand-in for political conservatives) are teaching in the entire College of Arts and Sciences:

Eleven departments out of 19 surveyed show zero registered Republican professors: government, philosophy, anthropology, astronomy, dance, ecology and evolutionary biology, German studies, neurobiology and behavior, Latino studies, mathematics, and music.

A sum total of 17 Republican professors were found teaching within the College of Arts and Sciences, with the largest amount being five in economics and three in history.

Chemistry has two of 48 professors, comparative literature has one of 41, computer science shows two of 86. The rest were found in linguistics, molecular biology and physics.

The College Fix derived its conclusions by cross-referencing the names of registerd voters and their party affiliations in Tompkins County, N.Y., where Cornell is located, with the names of faculty members on Cornell's roster:

Of the 671 scholars researched, almost 50 percent were registered Democrats, whereas only 2.5 percent were registered Republicans. About 33 percent could not be categorized, most likely because the registration name is different than their professorial name, or they are not registered to vote, or they are not registered to vote in Tompkins County. Another 13 percent were listed as “BLK,” meaning blank and defined as “no party affiliation” by the state.*

The College Fix findings jibe with those of the student newspaper, the Cornell Daily Sun, which reported in 2015:

Of the nearly $600,000 Cornell’s faculty donated to political candidates or parties in the past four years, over 96 percent has gone to fund Democratic campaigns, while only 15 of the 323 donors gave to conservative causes.

The Sun’s analysis of Federal Election Committee data reveals that from 2011 to 2014, Cornell’s faculty donated $573,659 to Democrats, $16,360 to Republicans and $2,950 to Independents. Each of Cornell’s 13 schools — both graduate and undergraduate — slanted heavily to the left. In the College of Arts and Sciences, 99 percent of the $183,644 donated went to liberal campaigns. The law school demonstrated the strongest conservative showing, with nearly 26 percent of its approximately $20,000 worth of donations going to Republicans. 

While some Cornell faculty members interviewd by the Sun said that conservatives generally seem to prefer non-academic careers such as consulting and think-tank employment to college professorships, others simply wrote off conservatives as anti-intellectual bigots who don't belong on campuses:

Other professors asserted that Republicans often have ideas that are “anti-science” or “anti-intellectual,” which can make them an unpopular presence at elite universities.

“It is not surprising that faculty at Cornell find the anti-scientific rhetoric of many in the Republican Party to be troublesome,” Prof. Kenneth McClane, English, said. “Many of us here are scientists — we believe in global warming, since we believe what the research tells us.”

[Government professor Richard] Bensel echoed this claim, saying that recent Republican debates have illustrated the deviation of “mainstream conservatives” from views that are widely accepted by intellectuals at reputable universities.

“I think many mainstream Republicans have views that are anti-intellectual and anti-science,” he said. “There are candidates who are creationists, don’t believe in climate change and claim that Obama’s a Muslim. Ted Cruz, for example, should not teach here.” 

Maybe conservatives shy away from college teaching because they don't want their days filled with harangues from the likes of McClane and Bensel.