This question has been in the news recently, in light of the recent House Committee hearings on “Holding Campus Leaders Accountable and Confronting Antisemitism.” A few thoughts on my part:
[1.] There’s no “advocacy of genocide” exception to the First Amendment, or to the contractual promises of student free speech that many private universities rightly implement.
[2.] Indeed, as I’ve argued before, it is important that students be free to debate what is proper to do in war, and what wars are just. War involves mass killing, in some wars by the millions. I think some such killing is atrocity and some is just. But different people draw the lines differently, and that is a matter that is quite rightly up for debate.
For instance, some people label the Israeli invasion of Gaza as “genocide.” I think they’re wrong, both as a moral matter and as a matter of international legal norms (such as they are). I think Israel is entitled to kill as many Hamas fighters as it can, and if Hamas hides behind civilians, then Israel is entitled to kill the civilians to get to Hamas. Likewise, I think the U.S. was quite right to kill many German and Japanese civilians in the course of fighting the German and Japanese militaries.
Students need to be free to make these arguments supporting the killing of civilians in Gaza, Germany, and Japan, without having their rights turn on what lines some international lawyers might draw. Likewise, pro-Palestinian students need to be free to argue that the state of Israel was wrongly created on Palestinian land, and that Israeli Jews need to be expelled from it—through mass relocation if possible, but if they want to fight (as of course Israelis will) through killing. Again, I think that morally there is a world of difference between these two positions. But I think that, for free speech purposes, both should be protected without regard to my moral views of the matter.
Likewise, if we focus less on the label genocide and more on the reality of mass killing of civilians, I think that even there people should be free to argue that this is legitimate under certain circumstances. For instance, while I understand that there are some arguments that Hiroshimi and Nagasaki included legitimate military targets, I think the strongest argument for bombing them was to show Japanese that continuing the war would cause mass civilian deaths, and only total surrender would avoid that. And I think that, under those circumstances, such deliberate killing of civilians is proper.
Similarly, I think that the argument that, “if Iran drops a nuclear bomb on an Israeli city, Israel should drop a nuclear bomb on an Iranian city, precisely to show ordinary Iranians that killing Israelis would lead to killing of Iranians,” is an argument that free speech principles protect, even though it would justify the killings not of a thousand people but of tens or hundreds of thousands. Again, I think the Hamas killings were unjustified, while the hypothetical bombing of Iran and the real bombings of Hiroshima and Nagasaki were justified, for various reasons but chiefly because of my sense of who is in the right in the underlying war. But that highly disputed moral distinction shouldn’t lead to a First Amendment difference, or a difference in how private universities apply free speech rules.
[3.] Of course, there are exceptions to First Amendment protection, particularly for true threats of illegal conduct, solicitation of illegal conduct, and incitement of illegal conduct. These, however, are narrow exceptions, and especially rarely arise as to advocacy of military violence overseas. For instance, incitement is defined as speech (1) intended to and (2) likely to cause (3) imminent illegal conduct. A rally expressing support for Hamas murders in Israel is highly unlikely to, for instance, lead more terrorists to imminently engage in criminal acts in Israel.
Likewise, a true threat of violence is (to oversimplify) a statement saying that I or my confederates will do something illegal to you (could be violence, could be vandalism, could be something merely civilly actionable, such as unlawful discrimination). “I’ll kill the Zionist leaders on this campus” is likely to be a punishable true threat; likewise for “I’ll kill the Palestinian leaders, because they are justifying Hamas.” “We Palestinians will push the Israelis into the sea” is not, because the threat is of what a military group (or a nation) will do in a foreign war. (“We’ll kill the Jews here in L.A.” is an unclear matter; it’s a threat of unlawful violence, apparently by the speaker and his confederates, but it’s not clear whether such a statement is too broad and thus not particularized enough to be a true threat. To quote U.S. v. Kelner (2d Cir. 1975), to be a true threat must be relatively “specific as to target,” though it’s not clear just how specific it needs to be.)
[4.] Now to “harassment,” a term that has often been brought up recently. As then-Judge Alito said (and other courts have echoed this), “There is no categorical ‘harassment exception’ to the First Amendment’s free speech clause,” Saxe v. State College Area School Dist. (3d Cir. 2001). What sort of speech may be punished as “harassment” isn’t well-settled. But lots of courts have struck down campus speech codes at public universities that purport to ban “harassment” (see some of the cases cited in this post).
And though there is likely some room for punishing unwanted individually targeted speech (repeated phone calls, e-mails, personal approaches, etc.), simply expressing offensive viewpoints to the public can’t be punished as “harassment,” consistently with the First Amendment (or with private universities’ voluntary adoption of free speech norms), even if some of the listeners will be highly and understandably offended by those viewpoints. That’s equally true for viewpoints calling for the destruction of Israel, for the invasion of Gaza, for violence against American police officers, for violence against abortion providers, for discrimination based on race, religion, sex, national origin, sexual orientation, or gender identity, and so on.
[5.] All this having been said, universities should prevent violence, vandalism, trespassing in faculty or administration offices, obstruction of students’ path to class, loud noise that unduly interferes with studying, and more. But they should do so regardless of students’ viewpoints, not because those are viewpoints are seen as supposed “advocacy of genocide.”