I argued below that professors shouldn't be fired even for expressing views that are downright evil. A big part of my argument was the slippery slope concern: That, in Justice Black's words, First Amendment rights "must be accorded to the ideas we hate or sooner or later they will be denied to the ideas we cherish." Let me speak in some more detail about why this slippery slope is a very serious concern.
Let's start with a standard criticism of slippery slope arguments, as applied here: Churchill said things that were unusually awful. Assume that you and I believe they are much worse than other statements that we think deserve to be explored in the academy, even if we might think they're wrong -- for instance, claims that the U.S. is on the wrong side in Iraq, claims that homosexuality is evil, claims that there are significant innate biological differences between racial groups in intelligence, claims that women are innately worse than men in science, and so on. (I think claims of racial intelligence difference need to be explored; from what I hear, they are factually mistaken, but we can only know that they are factually mistaken if scholars are allowed to seriously investigate the issue, and keep investigating it. Claims that Americans or Jews or blacks deserve to be slaughtered, on the other hand, I can do without.)
So we see a distinction between Churchill's vile views and other views. Why not act on this distinction? Why not say, yes, we'll fire Churchill, but, no, others shouldn't be fired based on other speech, precisely because there is a distinction to be drawn between the two. In the words of Wilbren van der Burg, "Someone who trusts in the checks and balances of a democratic society in which he lives usually will also have confidence in the possibility to correct future developments. If we can stop now, we will be able to stop in the future as well, when necessary; therefore, we need not stop here yet."
My answer is that we may be confident that Churchill's views are different from others' views, but we might doubt that others -- faculty, administrators, legislators, judges -- will draw the line correctly. They might indeed consider Churchill's case analogous to that of some professor who is arguing that homosexuality is evil, or that sex discrimination is sometimes proper, or what have you. And by setting a precedent allowing Churchill's firing, we will have made it easier for them to fire others.
Think how often people argue by precedent and analogy in such situations. Several messages I've gotten disagreeing with my position said that, well, surely a professor would be fired for expressing support for the Nazis during World War II, or for saying today that Jews should be killed, or the like -- and therefore Churchill should be fired, too. My view is that all these people should, loathsome as they are, be protected by academic freedom, precisely because otherwise this would set a precedent for the future. In our legal and political system, analogy and precedent are powerful forces, and we need to think hard about the precedent that we'd be setting.
Let me a bit more explicit, by identifying three particular ways that the slippery slope can work here.
1. The equality slippery slope. People often support equal treatment -- which is to say the same treatment for behavior that they think is similar enough. If there's a flat rule that professors may not be fired for expressing views hostile to certain groups (whether Americans, blacks, Jews, or what have you), then a lot of people may grudgingly tolerate a wide range of offensive speech.
But once speech that offends some groups becomes punishable, other groups (in what I call "censorship envy") would understandably ask: Why aren't we protected against views that we find equally offensive, even if you folks respond with some distinctions that we find unpersuasive? And some people may find it hard to resist such arguments. Once an exception is made for the rule, others will be added for the sake of equal treatment.
2. The attitude-altering slippery slope. People often (not always, but often) take a cue about what's permissible based on what's done. We might see firing Ward Churchill as an unusual event, something that's just barely allowed; and we might therefore plausibly reject firing people whose speech was even a little reprehensible.
But once he's fired, and others who say similar things are fired, those decisions may well become part of people's background assumptions of what's acceptable. "Well, we fired Ward Churchill for these statements; that must mean that it's OK to fire people for such statements; and that must mean that academic freedom isn't that strong a principle."
Of course, some people might adopt the attitude that it's fine to fire people only for the most heinous statements, and that it's still not permissible to fire people for any remotely legitimate commentary. But the danger is that people won't take such a nuanced view -- rather, they'll just conclude that because professors do get fired for their viewpoints, it's OK to fire people for their viewpoints.
3. The small change tolerance slippery slope. Finally, it's harder to mobilize political (or legal) opposition to small changes in degree than to big changes, or changes in kind. If there's a flat rule that tenured professors may not be fired for their political views, then any such firing -- whether of Churchill or of someone who has a thoughtful argument against homosexuality -- would be seen as a Big Deal. But if people are routinely fired for expressing extreme viewpoints, then it becomes that much easier for a university to fire people for expressing slightly less extreme viewpoints.
Sure, critics of the second firing may draw distinctions between one viewpoint and another. But the public will be a lot less interested in such criticisms based on fine differences in degree. "These are complicated judgments by professionals," the public may say. "It's established that it's fine for them to fire people based on viewpoint in some situations. Given that this new situation isn't that different from past situations, we'll give the university the benefit of the doubt."
And then, after someone is fired for expressing a slightly less extreme viewpoint than Churchill's, and that becomes the new standard for what's allowed, someone else will be fired for expressing a still less extreme viewpoint, and so on. Over time, the line may move through small steps -- and the public and courts might not stop the motion: Each step would be seen as too small to be worth fighting over, and small enough that we should defer to the university's judgment rather than making a mountain out of a molehill.
Now none of these mechanisms -- which are of course just briefly sketched here, since it takes me many pages to go into them in detail -- are sure to operate. We do sometimes draw distinctions that don't lead to much slippage. And sometimes we need to draw distinctions, even despite the risk of slippage. (One example: In the decision whether to hire or to tenure a faculty member, we inevitably have to consider the content of his scholarship, and no matter how we try to focus on the quality of the work regardless of whether we agree with the bottom line, it's inevitable that the person's views will color our judgment of the work's quality. But unless we are just to use content-neutral measures, such as the number of pages the person has written, this content-based evaluation is necessary, in spite of its risks. Deliberately viewpoint-based firings of tenured faculty members, on the other hand, are not necessary.)
Nonetheless, I think that allowing professors to be fired for their reprehensible viewpoints poses very large slippery slope risks. Narrow exceptions to academic freedom protection are especially likely to become broader, for all the reasons I give above. And that's dangerous enough that I think we should protect some evil people like Churchill rather than risk stripping protection from all faculty members who express unorthodox viewpoints.