What should be done about law-school deans and others in legal institutions who censor, cancel, blacklist, refuse to hire, fire, “investigate” and otherwise threaten others for their opinions? A partial answer lies in reminding them that their misconduct may disqualify them from ever sitting on the bench. At one point or another, most lawyers dream about being a judge. Lawyers and aspiring lawyers should remember that their conduct today may be the measure of their disqualification tomorrow.

The question came up last week at Georgetown Law School, when the dean, William Treanor, put a newly hired administrator and senior lecturer, Ilya Shapiro, on leave pending an investigation—merely because of a tweet about the pending Supreme Court nomination. Leaving aside that nonacademic opinion is no reason for punishing an academic, Mr. Treanor’s reaction is one more case of harassing dissenters.

The problem is now pervasive in law schools. On account of mere dissent, deans investigate faculty for their views, give them meager salary increases, bar them from teaching some subjects, and even threaten to fire them—as at Georgetown. It’s not only deans. Faculties or their appointment committees regularly refuse to hire people with the wrong views. Just as bad, student law-review editors exclude dissenting students from their boards and even threaten to fire editors whom they discover to have the wrong views, whether on pronouns or matters of law. Student editors also refuse to publish perspectives they dislike—at some journals, they have blocked conservative perspectives, originalist arguments, and “anti-administrative” (aka constitutional) positions. Many students and faculty therefore shy away from exploring such viewpoints. Quietly in the background, members of faculty oversight boards encourage or permit this narrow-mindedness. Cases therefore increasingly come before the courts, even the Supreme Court, with much academic literature on one side and little on the other. The intolerance thus becomes a due-process problem.

Elsewhere in the legal world, law firms discourage associates, even partners, from taking pro bono cases for dissenting individuals. At many large firms, representing terrorists after 9/11 was fine, even admirable. Now, representing conservatives can be a risky move for a young lawyer. Whether in bar associations or law firms, there are serious consequences for due process.

The situation has become so serious that it’s increasingly difficult to find academics and others to write or sign friend-of-the-court briefs on key issues—including freedom of speech. Many lawyers, even if apparently secure in tenure or partnership, are, if not afraid, uncomfortable being associated with what seem hazardous points of view.

What’s to be done? In the legal world, the first step is to remember that people who are intolerant aren’t fit to serve as judges or in other positions of legal authority.

If a dean, committee member, law-review editor, bar-association leader, or other person in authority cancels, blacklists, excludes, threatens or otherwise disadvantages scholars, students, lawyers or their work on the basis of their opinions, can he be trusted as a judge to listen with an open mind to conflicting legal positions? If someone can’t tolerate both sides, how can he be trusted to do justice impartially?

Otherwise-decent faculty, students and partners often go along with intolerance because they lack the stomach to protest it. They may tell themselves they’d do better on the bench. But academics have tenure, and partners have much financial security. So there’s little reason to think they’ll do better as judges.

The position of a judge is unlike any other job. Judges enjoy vast authority over their fellow Americans, and the primary defense against abuse of this authority is their internal commitment to impartiality—their dedication to hearing both sides with an open mind and deciding without prejudice. This is a constitutional requirement of judicial office and due process.

So it’s not too much to consider intolerance or cowardice disqualifying. Those who have shown themselves to be intolerant of difference or too fearful to stand up for what is right have no business sitting on the bench.