A sociology professor at the University of California Santa Barbara is in the center of a heated debate about academic freedom after he sent an e-mail comparing "parallel images of Nazis and Israelis" to 80 of his students in January.

Two of William Robinson's students dropped out of his sociology of globalization class after they received the e-mail. The message also caught the eye of at least two national Jewish groups, including the Anti-Defamation League, which has called upon the tenured professor to "unequivocally repudiate" it.

"If Martin Luther King were alive on this day of January 19, 2009, there is no doubt that he would be condemning the Israeli aggression against Gaza along with the U.S. military and political support for Israeli war crimes, or that he would be standing shoulder to shoulder with the Palestinians," the 50-year-old Robinson wrote in his e-mail.

"I am forwarding some horrific, parallel images of Nazi atrocities against the Jews and Israeli atrocities against the Palestinians."

Dozens of photographs followed, depicting Holocaust victims in Nazi Germany and nearly identical images from the Israeli attack on Gaza. Robinson included a note that "Gaza is Israel's Warsaw."

Click here to view one of the images (warning: graphic material).

The two students who dropped out of Robinson's class accused him of violating faculty code of conduct by disseminating personal or political matter unrelated to the course.

"I felt nauseous that a professor could use his power to send this email with his views attached, to each student in his class," senior Rebecca Joseph wrote. "Due to this horrific email I had to drop the course."

Click here to view one of the images (warning: graphic material).

Robinson, who is Jewish and has been teaching at UCSB for nine years, is defending his message. He says the university's ongoing investigation is an attack on his academic freedom. He did not respond to repeated requests for comment.

In a letter to Robinson and UCSB Chancellor Henry Yang, Cynthia Silverman, regional director of Santa Barbara's Anti-Defamation League chapter, described the professor's comparison as "offensive" and said it "crossed the line well beyond" legitimate criticism of Israel.

Click here to view one of the images (warning: graphic material).

"We also think it is important to note that the tone and extreme views presented in your email were intimidating to students and likely chilled thoughtful discussions on the Israeli-Palestinian conflict," Silverman wrote.

But Robinson's supporters, including prominent professor of linguistics Noam Chomsky, say the university's probe is improper and is an attempt to silence criticism of Israel.

"Unfortunately, there has been a wave of similar efforts to undermine academic freedom throughout the country in recent years," Chomsky wrote in a letter to Yang. "I hope and trust that the university will take a clear and strong stand in favor of principles that are central to free inquiry and expression, particularly so in a distinguished institution of higher learning such as this one."

A group called the Committee to Defend Academic Freedom at UCSB, which includes professors and Robinson's former students and teaching assistants, has been formed to back the professor. The group's Web site includes a letter of support and a call for an apology to Robinson from the California Scholars for Academic Freedom, which represents more than 100 professors from 20 colleges.

"The right to present controversial material in the context of a course — including opinions that may be deeply disturbing to some students — is an essential element of academic freedom," the group wrote. "This includes the right to criticize government actions, whether they be American, Israeli, or those of any other government."

Paul Desruisseaux, a UCSB spokesman, said a faculty committee has been formed to determine whether the case should be considered by school administrators.

"Given the nature of this case, there are some aspects of censure that could possibly by imposed that could probably fall short of dismissal," Desruisseaux told FOXNews.com. "And it's possible that this initial committee could determine it was just bad judgment. We need to let this process run its course."

Whatever the outcome of Robinson's case, a chilling effect will likely follow, particularly on local academics, according to Cary Nelson, national president of the American Association of University Professors.

"Some faculty will take it as an opportunity to exercise their free speech rights while others won't because they don't want calls from 20 reporters," Nelson said. "You'll get a dual effect."

Nelson, whose organization has not announced a formal opinion on Robinson's actions, said the professor appears to be in the clear.

"We wait and watch that inquiry," Nelson said. "It's easy to imagine how a course in globalization made some comparisons between different historical periods and different historical events.

"If it is related to class discussion, it is almost certainly to be covered by academic freedom."