Breitbart editor and right-wing provocateur Milo Yiannopoulos has courted controversy at every stop on his recent, multi-state college tour—meeting admirers and, more often than not, adversaries. At the numerous colleges and universities he has visited as part of his “Dangerous Faggot Tour,” Yiannopoulos has prompted peaceful protests, but also disinvitations and shout-downs by some students who say his words (he’s frequently accused of racism, misogyny, and more) have no place on their campus. Of late, a number of his events have been subjected to a more subtle—but equally dangerous—form of censorship: security fees.

The Miami Herald reported that the University of Miami College Republicans recently decided not to host Yiannopoulos after the group and UM administrators failed to agree on the “operations and logistics needed to host the speaker.” In short, there were security concerns. Earlier this year, DePaul University charged its College Republicans $1,000 to ensure security at a Yiannopoulos event, and then denied a second event altogether. Vice President of Student Affairs Eugene Zdziarski explained his reasoning in an email:

Mr. Yiannopoulos’ words and behavior contained inflammatory-speech, contributed to a hostile environment and incited similar behavior from the crowd in attendance. In addition, he led an unapproved march through campus that created a potentially dangerous situation.

Whatever one’s views on Yiannopoulos, the reality that most offensive or hateful speech is protected on public campuses under the First Amendment is unchanged. The Supreme Court addressed the issue of using hurtful speech on public property in holding that the First Amendment protected the expression of the Westboro Baptist Church at funeral pickets on public property:

Speech is powerful. It can stir people to action, move them to tears of both joy and sorrow, and—as it did here—inflict great pain. On the facts before us, we cannot react to that pain by punishing the speaker. As a Nation we have chosen a different course—to protect even hurtful speech on public issues to ensure that we do not stifle public debate.

The same reasoning applies at public college campuses. In Healy v. James (1972), the Court wrote: “[T]he precedents of this Court leave no room for the view that, because of the acknowledged need for order, First Amendment protections should apply with less force on college campuses than in the community at large. Quite to the contrary, ‘the vigilant protection of constitutional freedoms is nowhere more vital than in the community of American schools.’”

While some of the universities at issue here, like like UM and DePaul, are private institutions not legally bound by the First Amendment, they are bound by the promises of free speech that they make to their students.

Now let’s take a close look at what security fees are, and how they’re used to censor campus speech.

What are content- and viewpoint-based security fees?

Often, universities will charge student organizations extra security fees to host an event on campus if there is concern that the views expressed by the speaker could lead to disruption or violence by protestors.

Several recent high-profile campus incidents and event cancellations involving controversial speakers have brought renewed attention to these kinds of fees: efforts to prevent Ben Shapiro from speaking at California State University, Los Angeles (CSULA), the Yiannopoulos incident at DePaul and a separate one involving Shapiro, and the cancellation of a speaker at Kansas’ Newman University. In yet another DePaul incident that we reported just last week, the school charged the DePaul Socialists a security fee for simply hosting their first fall meeting. (And this was after we wrote about why DePaul might be “America’s Worst School for Free Speech.”)

Despite the recent uptick in security fees cases, however, impermissible content-based security fees have been a major trend since at least 2009.

That year, we wrote to the University of Arizona; the University of California, Berkeley; the University of Colorado at Boulder; and the University of Massachusetts Amherst about the respective security fees they’d each attached to controversial speakers there. Since that time, we’ve seen more such cases at schools like Temple University (2010), Montclair State University (2011), Boise State University (2014), and Stanford University (2014) just to name a few.

In 2009, we called security fees the new “censorship tool of choice” among administrators. It’s safe to say that this year, we have seen a resurgence of that phenomenon.

Why are content- and viewpoint-based security fees unlawful?

Security fees are unlawful at public universities because they function as a tax on protected speech.

In Forsyth County v. Nationalist Movement (1992), the Supreme Court determined that government actors—like public college or university administrators—may not lawfully impose security fees based on their own subjective judgments about “the amount of hostility likely to be created by the speech based on its content.” Such fees amount to a tax on speech an administrator subjectively dislikes, or subjectively believes is likely to cause disruption or violence.

“Speech cannot be financially burdened, any more than it can be punished or banned, simply because it might offend a hostile mob,” the Forsyth Court wrote, noting that “[t]hose wishing to express views unpopular with bottle throwers, for example, may have to pay more for their permit.”

Speech protected by the First Amendment is “free” speech—in both senses of the word. Content- and viewpoint-based security fees allow the government to arbitrarily affix a price tag to some speech on the basis of the speaker’s viewpoint.

Security fees also serve as an invitation to the “heckler’s veto.” One of the ways a heckler’s veto can manifest itself on campus is when students shout down or interrupt a speaker with whom they disagree, preventing the speaker from exercising their own right to speak. The possibility that groups hosting controversial or unpopular speakers will be subject to burdensome security fees incentivizes those who disagree with a speaker to threaten disruption so as to make those fees come to fruition.

This is unconstitutional at public universities. And at private institutions that are not bound by the First Amendment but nonetheless promise free speech, this form of censorship prevents those promises from being upheld.

Schools may institute security fees only in a manner that is both content- and viewpoint-neutral. The fees must also be imposed based on narrowly-drawn, reasonable and published definite criteria.

As the Court wrote in Forsyth, “Listeners’ reaction to speech is not a content-neutral basis for regulation.”

As Milo Yiannopoulos’ tour continues—he’s got more than a dozen stops scheduled for next month alone—FIRE anticipates seeing continued implementation of content- or viewpoint-based security fees. But we’ll keep referring administrators to this post to remind them that they can’t use security fees as a form of censorship. As long as censorship is present on campus, FIRE will be there to try and put a stop to it.