But there’s reason to believe widespread reliance on adjunct faculty may encourage the very radicalism conservatives fear. Social scientists have found that when aspiring intellectuals face highly restricted employment opportunities, they often take refuge in extreme politics. In a 1996 study, the sociologist Jerome Karabel sought to identify the circumstances under which intellectuals, from would-be academics to writers and artists, embrace or rebel against the status quo. “Especially conducive to the growth of political radicalism,” he wrote, “are societies in which the higher levels of the educational system produce far more graduates than can be absorbed by the marketplace.”

Frustrated that their long investments in education and cultural cultivation haven’t paid off, intellectuals in such societies train their anger — and ideas — at the economic and political systems (and social groups) they hold responsible. Professor Karabel cited the example of Germany in the 1930s, when a slow-moving academic labor market increased the appeal of Nazism for a surprising number of underemployed intellectuals.

The same situation can breed support for radical movements of the left. Poor job prospects for American thinkers during the Depression helped draw many into socialism or communism. More recently, the sociologist Ruth Milkman found that well-educated millennials were overrepresented among Occupy Wall Street activists. These young people had spent their lives diligently preparing to enter the knowledge economy and became disillusioned when, after the financial crisis, it all seemed to be crashing down.

It’s not hard to understand why American adjuncts today would feel frustrated with their lot. Throw that into the mix alongside the heated politics of the Trump era and you’ve got a recipe for outrage.

Of course, most people in academia — a famously progressive occupation — are outraged these days, and activism and political engagement are up across the board, as the times demand. But those lucky enough to have landed coveted tenure-track or tenured posts generally recognize that they have too much to lose to become “antifa” rioters or rant uncontrollably on social media, even if they have stronger academic freedom protections than their adjunct colleagues. In a sense, the tenure system has tamed them, and much of their protest will remain merely academic.

The occasional shocking public statement from an adjunct instructor should serve as a reminder of the volatility that comes when — in higher education or outside it — we allow employment conditions to deteriorate to whatever the market will bear.