One way or the other

 Megan McArdle writes "Public trust in universities has plummeted over the past decade, among independents as well as conservatives, which is why Republicans now feel so free to attack them."  McArdle says that the major reason that trust has declined is that the prevailing political climate in universities has moved to the left:  they developed "a left-wing culture that appeared increasingly hostile to the society paying its bills."  It is true that the political climate at universities is well to the left of the nation as a whole, but that isn't a recent development:  the culture at leading universities has been moving to the left for a long time.  So if that's the cause, we should see a gradual decline of confidence over a long period of time.  Between the 1970s and the early 2010s, the Harris Poll regularly asked how much confidence you had in the "people in charge of running major educational institutions, such as colleges and universities."  There wasn't much trend--it declined from the 1970s to the 1990s and then bounced back (see this post).  Gallup started asking a similar question in 2015, and confidence declined substantially between 2015 and 2024.   Since the decline in confidence is limited to the last decade or so, the cause must also be a relatively recent development.  McArdle offers another possibility:  "the value of a college degree is stagnant and might fall as AI takes over much knowledge work."  The timing on this is a better fit:  payoff to a college degree rose until about 2010 and has stayed about the same, or maybe declined a little, since then.  However, the claim that stability in the college wage premium leads to a decline in confidence doesn't make sense:  it amounts to saying that people want to see college graduates continue to pull away from everyone else.

What if she has it backwards:  Republicans have attacked universities over the past decade, so public trust (especially among Republicans) has plummeted?  I don't have any measure of Republican rhetoric about universities, but my impression is that it has become increasingly negative in the past ten years or so.  There also seems to have been an increase in media coverage of campus "activism":  two prominent examples, at Yale and the University of Missouri, happened in 2015, and there have been many more since then.   Since 2023, there have been many protests about the conflict in Gaza.  The rate of very little or no confidence answers rose from 23% in 2023 to 32% in 2024, and then fell back to 23% in 2025.  That suggests that changes in public opinion are partly a reaction to actual events; although there were a lot of protests in 2024-5, they were less disruptive and administrations handled them more effectively (the surveys are taken in June).  There's also probably also a self-reinforcing process of more coverage creating more interest and more interest creating more coverage.