The school called off a planned appearance by the Wheels of Justice tour last week, just hours before the group was scheduled to arrive in Andover. Tom Meyers, president of the Andover Education Association, has contacted the American Civil Liberties Union and said he will take the school to court if administrators do not reverse the decision.

"My First Amendment rights, and the rights of my teaching colleagues and our students, have been denied," said Meyers, a social studies teacher.

Speakers from the Wisconsin-based Wheels of Justice tour were supposed to come to Andover High on Friday to discuss the Israeli-Palestinian conflict and the war in Iraq. But Thursday afternoon, High school principal Peter Anderson called Meyers and said the event was off.

Superintendent Claudia Bach declined comment, and Anderson did not return phone calls yesterday. Meyers said Anderson told him the visit was cancelled because of "political pressure."

The Anti-Defamation League and Rabbi Robert Goldstein of Temple Emanuel in Andover both voiced their opposition to Andover High last week. Andrew Tarsay, the ADL's regional director, applauded the school's decision.

"Wheels of Justice is neither factual nor balanced," he said. "This group is viciously anti-Israel."

Goldstein called Wheels of Justice an "extremist" group whose messages "border on propaganda." He suggested the school instead hold a forum, where speakers on both sides of the Israeli-Palestinian conflict could share the stage.

"Then you get the benefit of them questioning each other," Goldstein said. "The more kids are exposed to, the better. It's not what perspectives kids hear, it's how it's done."

That kind of forum is what occurred during the last Wheels of Justice visit to the Merrimack Valley, when the group spoke at North Andover High School in 2004. There was concern about the organization's message then, too, but the school invited a veterans group and Goldstein to make it a more balanced event.

Andover High teachers were working to present the Israeli perspective at their school later this year, Meyers said. He described Wheels of Justice as "an organization that supports human rights and attempts to do nonviolent work."

Sarah Wunsch, a staff attorney for the ACLU of Massachusetts, wrote a letter to the School Department's lawyer Friday, saying Andover High students "should not be shielded from what some deem to be controversial views." Meyers distributed the letter to teachers yesterday morning.

Wheels of Justice stops at schools, colleges, churches and community groups throughout the country, and the resistance met in Andover is "very, very rare," tour manager Dan Pearson said. "We've been to hundreds and hundreds of high schools with no problem."

The cancellation is not the first time the Israeli-Palestinian conflict has caused a stir at Andover High. Last spring, a former student now living in Israel wrote a letter to a local newspaper, questioning if physics teacher Ron Francis is fit to educate students there. Francis has defended Hamas and is a member of the Somerville Divestment Project, which opposes financial investments that benefit Israel.

At the time, Anderson said he had not received any other complaints about Francis, and Goldstein defended Francis' right to have those beliefs. Francis was the teacher who first contacted Wheels of Justice about coming to Andover High, Pearson said.