For three decades, left-wing extremists have dominated American academics, spouting odd but seemingly harmless theories about "deconstruction," "post-modernism," "race, gender and class," while venting against the United States, its government and its allies.

Only these ideas are not so harmless. The radical notions espoused in the classrooms and in campus demonstrations have recently had dangerous consequences. These are especially visible with regard to the Arab-Israeli conflict.

Consider some of the steps American professors took during 2002:

* Columbia University: Hamid Dabashi, a specialist on Iran, compared Israel's military maneuvers in Jenin (to prevent future suicide bombings) with the Nazi Holocaust. When one student protested his canceling class to attend a rabidly anti-Israel sit-in, he sneeringly replied, "I apologize if canceling our class in solidarity with [Palestinian] victims of a genocide . . . inconvenienced you."

Joseph Massad, a Jordan specialist at Columbia, spoke at that same anti-Israel rally, calling Israel "a Jewish supremacist and racist state" that, he proclaimed, "should be threatened." This is in addition to a talk with the inflammatory title "On Zionism and Jewish Supremacy" and a course that (students report) served as a soapbox for anti-Israeli polemics.

* SUNY-Binghamton: Robert Ostergard of the political-science department converted his course into an anti-Zionist platform. One guest speaker, Ali Mazrui, presented a lecture that a student called "a 45-minute diatribe against Israel" equating Zionism with fascism, Israel with apartheid South Africa and Prime Minister Ariel Sharon with Hitler.

* Kent State University, Ohio: Julio César Pino of the history department published an ode to a Palestinian suicide bomber, lauding her courage and calling on Allah to "elevate your place in paradise."

* University of Oregon: In a course entitled "Social Inequality," the sociology department's Douglas Card reportedly called Israel "a terrorist state" and Israelis "baby-killers" and insisted that students agree with his view that Israel "stole land" on the final exam. One student said Card bashed Israel and Jews "at every opportunity."

* UC-Berkeley: The English department's Snehal Shingavi, a leader of "Students for Justice in Palestine," announced a course on "The Politics and Poetics of Palestinian Resistance" with the now-infamous "warning" to conservatives "to seek other sections."

In brief, instructors routinely tout wild-eyed politics and openly wield their authority to indoctrinate students. At times, they even admit this, as in the case of Andrew Ross, the then-Princeton English professor who boasted in 1990 that he was using his position to radicalize "the children of the ruling class."

Not surprisingly, some interpret all this as implicit permission to harass Jewish and pro-Israel students. The result: a wave of verbal and physical attacks.

* At San Francisco State University, anti-Israel students physically threatened students marching for Israel while shouting phrases like, "Die, you racist pigs," and "Hitler should have finished the job," prompting the school's president to admit that he was never "as deeply distressed and angered by something that happened on this campus" in his 14 years there.

Even after this incident, pro-Palestinian students continued to use an SFSU-owned Web page to engage in Holocaust denial and accuse Jews of ritual murder.

* At Berkeley, anti-Israel students occupied a classroom building, leading to the arrest of 79 of them, including one charged with a felony for biting a police officer.

* At the University of Colorado at Boulder, students desecrated an Israeli flag and chalked anti-Semitic slogans on the main campus walkway.

* At the University of Illinois, they assaulted with rocks a home flying an Israeli flag, shattering the front window.

Although professors teaching Middle East-related courses are the most responsible for this degeneration on campus, others, too, are complicit. By indulging the Middle East specialists' radicalism and efforts at indoctrination, alumni, administrators, parents, other faculty, Education Department officials and state legislators effectively condone those activities.

The time has come for all these stakeholders to take back the universities as institutions of civilized discourse. This can be done only by ending the now-regnant atmosphere of extremism and intimidation. The place to start is by condemning and curbing the leftist activism that too often passes for Middle East scholarship