Dorothy virtuously proclaimed that there is no place like home -- even after an adventurous trip to the Emerald City. Historically the common law did not agree.

Under the in loco parentis doctrine, school authorities had the same rights as parents, or nearly so, to make rules for students in public schools and universities. In the not-too-distant past, school officials for example might regulate political speech on campus and student sexual behavior, even if consensual. School leaders were expected to make moral judgments for students and to enforce them. In a paternalist regime, due process was not required to impose discipline, including suspension. Then came the post-World War II era, the Free Speech Movement, and a sea-change in due process norms. Students asserted that they were entitled to be treated as adults with a wide range of speech and other rights. They won in practice and often in the courts; paternalism was in tatters.

But now there is a nascent, however subconscious or inadvertent, effort to reinstate in loco parentis. The celebration of the 50th anniversary of the Free Speech Movement was met with heckling and disruption at the University of California, Berkeley. At Haverford College and elsewhere, graduation speakers have been disinvited if some students detest their points of view. Speakers perceived as pro-Israel are routinely disrupted; a mob of students prevented the mayor of Jerusalem from speaking at San Francisco State. Universities have been called upon to keep campuses safe from critics of Black Lives Matters, the NRA, affirmative action, and "Trump 2016" chalk scribblings on sidewalks. Sometimes administrators criticized the speech; in other cases they censored or meted out discipline.

When the master of Sillman College at Yale defended free expression in the choice of Halloween costumes, he was surrounded by angry students. One young woman was videotaped saying: "Be quiet! In your position as master it is your job to create a place of comfort and home for the students that live in Sillman. You have not done that." At Northwestern a feminist professor wrote an essay on campus sexual politics. Two students alleged that the essay created a hostile environment, demanding corrective action by the university.

Universities are being asked to act as parents. Parents have broad moral authority over their children. If a parent may determine a child's access to the internet, decline to invite racist Uncle Charlie over for dinner, impose a curfew on date nights, or celebrate a boys-only birthday party, why can't a university perform a similar function?

I suspect the new paternalists would be far less enthusiastic about some of these measures; they are for selective application of the in loco parentis doctrine. It applies only when one disagrees with the speaker. In this view the First Amendment is at best an inconvenience and at worst an excuse for protecting insulting speech. Apparently some campuses are irony-free zones.

A recent survey found that more than two-thirds of college students support the idea that disciplinary action is appropriate in response to racist, homophobic and other offensive speech. Why has this view taken hold? Some think it is because students were often indulged by their permissive families; they lead privileged lives. I am skeptical. Students and their families went through the Great Recession and often face economic hardships and an uncertain job market. Students of color often face particular challenges. And student upset with offensive speech goes back many decades. Speech has often been perceived as hurtful. Consider, for example, the adoption of racial harassment codes in the 1980s -- which generally were declared unconstitutional by lower courts.

My view is that much progress has been made in addressing overt acts of discrimination by universities. Now the target has moved from hateful action to perceived hateful speech. It is an understandable evolution, though it reflects an ignorance of constitutional traditions. The evolution is in part sustained by an intellectual movement focusing on dog whistle discrimination, implicit bias and sensitivity to micro-aggression. As University of California, Irvine professors Howard Gillman and Erwin Chermerinsky have written, students are now "deeply sensitized to the psychological harm associated with hateful or intolerant speech, and their instinct is to be protective."

The university in many senses is a home away from home, protecting students and keeping them physically safe. In addition to teaching and research, it often provides food, recreational opportunities, and health and counseling and other services. Of course a university may provide spaces for people who share an identity or a viewpoint and keep others from disrupting their community. Of course it may nurture diversity and seek to eliminate discrimination and frictions among groups. Of course universities may provide moral leadership by condemning hate speech. And professors may choose to give students advance notice that a classroom topic may offend some -- though I would urge the students to confront their nemeses.

But universities are not homes, administrators are not parents. University students are not children. Students should not be protected from ideas and communications that they find disturbing. Robust speech, protected by the First Amendment, often may offend or chill or disrupt the conventional wisdom. That is good. Universities should work to protect students from sexual and physical assaults and other harms. They should not be safe havens from disturbing ideas and discourses. It is one thing to condemn and quite another to censor or punish.

We live in an era in which people can easily isolate themselves ideologically. Not only may the home be a vacuum-sealed bubble, but people can go only to the websites or the cable news channels that reinforces their points of view. They can hang out largely with fellow ideologues. Behavioral economists call this confirmation bias. But universities are one of the few places (the work place should be another) where one encounters others with different points of view and engages in robust debate. Universities should seek to undermine confirmation biases. Effective democracy requires reflective, critical and well-informed participants. Universities should be educating for democracy.

Mark Yudof is the former president of the University of California, former chancellor of the University of Texas, and chair of the advisory board of the Academic Engagement Network. Website: academicengagement.org