Efforts to suppress politically incorrect speech on campus continue apace, as seen in the hostility directed toward Michael Oren, Israeli ambassador to the U.S., during a lecture on February 8 at the University of California, Irvine. Based on this and other recent events, one may identify four general villains in the struggle to uphold the rights of speakers:

Boorish students. To quote Richard L. Cravatts, these are people with "no interest in listening to, or letting others listen to, ideas that contradict their own worldview." Mostly Muslim versions were out in full force at UCI, shouting invective at Oren on ten separate occasions and aiming to silence him. At one point, he took a twenty-minute break as school officials expressed their embarrassment and disgust. Eleven ruffians were escorted from the venue and arrested.

We have seen such behavior before. Daniel Pipes experienced his own run-in with "goons of an Islamist persuasion" at Irvine in 2007. Later that year, a lecture by Islam critic Nonie Darwish at Berkeley suffered frequent interruptions, while one by conservative activist David Horowitz at Emory had to be abandoned due to an unruly crowd. Nor is the problem limited to the U.S. In February, Israeli minister Danny Ayalon encountered racial abuse at Oxford. And on and on.

Islamist pressure groups. Organizations like CAIR, MPAC, and MAS joined the enemies of free speech by defending the UCI students and calling on administrators to drop disciplinary action. CAIR stated that "the right to freely express one's opinions is a most sacred freedom protected by our Constitution," but failed to note that speakers and other parties also have rights. MPAC praised the students' "courage and conscience to stand up against aggression" and demanded that the arrests be investigated. MAS even compared the obnoxious kids to Martin Luther King. Hence, shouting down speakers now has the blessing of prominent Muslim groups.

Adversarial campus officials. Though UCI vigorously defended free speech at the Oren event, its diligence is the exception to the rule. Not only do most U.S. universities employ speech codes, but administrators and professors have worked overtime to derail visits by anti-Islamists at countless schools. Among recent outrages: charging student groups for the extra security needed to protect lecturers from angry mobs, eleventh-hour requests that formats be altered, and very public condemnations of students organizing frowned-upon talks.

Cowed students. Equally frustrating, though perhaps somewhat forgivable, is that students who should know better often cave to the collective pressure. For example, following Muslim objections, Princeton's Tigers for Israel withdrew its sponsorship of an appearance last November by Nonie Darwish; it was quickly canceled. Similarly, in February of this year, the Israel Society at Cambridge called off an address by Israeli historian Benny Morris, citing fears of "being portrayed as a mouthpiece of Islamophobia" after some Muslims criticized his work.

Popular speech does not require protection; unpopular speech does. The paucity of such protections in academic communities is disturbing. More disturbing: that pro-Western, pro-Israel, anti-Islamist speech is unpopular among so many administrators, professors, and students.