After Donald Trump’s election, some universities echoed with primal howls. Faculty members canceled classes for weeping, terrified students who asked: How could this possibly be happening?I share apprehensions about President-elect Trump, but I also fear the reaction was evidence of how insular universities have become. When students inhabit liberal bubbles, they’re not learning much about their own country. To be fully educated, students should encounter not only Plato, but also Republicans.

We liberals are adept at pointing out the hypocrisies of Trump, but we should also address our own hypocrisy in terrain we govern, such as most universities: Too often, we embrace diversity of all kinds except for ideological. Repeated studies have found that about 10 percent of professors in the social sciences or the humanities are Republicans.

We champion tolerance, except for conservatives and evangelical Christians. We want to be inclusive of people who don’t look like us — so long as they think like us.

I fear that liberal outrage at Trump’s presidency will exacerbate the problem of liberal echo chambers, by creating a more hostile environment for conservatives and evangelicals. Already, the lack of ideological diversity on campuses is a disservice to the students and to liberalism itself, with liberalism collapsing on some campuses into self-parody.

At Oberlin College soon after the election, students erupted in protests after a local bakery was accused of racial profiling of a black student in a shoplifting case. The student senate endorsed a boycott of the bakery, and demonstrators carried signs calling the owner a racist.

But allegations of a pattern of racist behavior were undermined by police records showing the overwhelming share of people detained for shoplifting at the bakery were white. This may actually have been a case of liberal hysteria.

Some of you are saying that it’s O.K. to be intolerant of intolerance, to discriminate against bigots who acquiesce in Trump’s record of racism and misogyny. By all means, stand up to the bigots. But do we really want to caricature half of Americans, some of whom voted for President Obama twice, as racist bigots? Maybe if we knew more Trump voters we’d be less inclined to stereotype them.

Whatever our politics, inhabiting a bubble makes us more shrill. Cass Sunstein, a Harvard professor, conducted a fascinating study of how groupthink shapes federal judges when they are randomly assigned to three-judge panels.

When liberal judges happened to be temporarily put on a panel with other liberals, they usually swung leftward. Conversely, conservative judges usually moved rightward when randomly grouped with other conservatives.

It’s the judicial equivalent of a mob mentality. And if this happens to judges, imagine what happens to you and me.

Sunstein, a liberal and a Democrat who worked in the Obama administration, concluded that the best judicial decisions arose from divided panels, where judges had to confront counterarguments.

Yet universities are often the equivalent of three-judge liberal panels, and the traditional Democratic dominance has greatly increased since the mid-1990s — apparently because of a combination of discrimination and self-selection. Half of academics in some fields said in a survey that they would discriminate in hiring decisions against an evangelical.

The weakest argument against intellectual diversity is that conservatives or evangelicals have nothing to add to the conversation. “The idea that conservative ideas are dumb is so preposterous that you have to live in an echo chamber to think of it,” Sunstein told me.

Of course, we shouldn’t empower racists and misogynists on campuses. But whatever some liberals think, “conservative” and “bigot” are not synonyms.

One of America’s most eminent scientists is Francis Collins, an evangelical Christian who is director of the National Institutes of Health. Few scholars had as much impact on modern thought as Gary Becker, the conservative University of Chicago economist. Condoleezza Rice, a secretary of state for George W. Bush, would add value to any campus.

I’m not arguing for affirmative action for conservatives — partly because conservative academics say they don’t want preferences. But I do think we can try harder to recruit job applicants who represent diverse views, to bring conservative speakers to campuses and to avoid a hostile work environment for conservatives and evangelicals.

We’re seeing an uptick in hate crimes in society tied to Trump’s rise, and the last thing we need on campuses is reciprocal illiberalism, this time led by liberals.

As individuals, we can also follow smart people on social media whom we disagree with. In my latest email newsletter, I suggest some conservatives to follow.

I fear the damage a Trump administration will do, from health care to foreign policy. But this election also underscores that we were out of touch with much of America, and we will fight back more effectively if we are less isolated.

When universities are echo chambers, they become conservative punch lines, and liberal hand-wringing may be one reason Trump’s popularity has jumped since his election.

It’s ineffably sad that today “that’s academic” often means “that’s irrelevant.” One step to correcting that is for us liberals to embrace the diversity we supposedly champion

<NICHOLAS D. KRISTOF>