History teacher Bill Schechter and high school senior Ted Griswold believe their lawsuit is about a worthy and innocent educational principle: presenting different views of a tricky and disputed historical topic. The Lincoln-Sudbury Regional High School teacher and his student believe that when Massachusetts high school students learn about the deaths of at least 1 million Armenians in Turkey during the early part of the 20th century, they should be taught that, while many historians call it a genocide, there are some who disagree.

But to the Armenians caught up in those horrific events and their descendants, the lawsuit dishonors the people who died in massacres and forced deportations committed by the Turks. They say presenting opposing views of those events is like denying the Holocaust or saying the earth is flat. And they say the case has reopened a battle many Armenians in Massachusetts thought they had already won.

"It is a major insult to those who died during the genocide, and for those survivors who are now listening to this being questioned," said Aram Chobanian, president emeritus of Boston University, whose grandfather and great-grandfather were killed during that period. "You bring back these memories to these people, the trauma and the horrible experiences. . . . There is no dispute in terms of whether it is a genocide or not. It is an affront that it's still being questioned."

At issue are events in the Ottoman Empire in 1915, in which more than 1 million Armenians died and many more were driven from their homes in what is now Turkey. Armenians have long maintained that the deaths and deportations were the results of a concerted effort by the Turks to eradicate them genocide. Many historians, and some European nations, agree with them.

Although the US government has stopped short of calling the events of 1915 genocide, Massachusetts lawmakers have been far friendlier to the Armenian position. In the Commonwealth, home to about 30,000 Armenians, state legislators established a day of remembrance for victims of the Armenian genocide. The Globe once prohibited the use of the word genocide to describe the 1915 events, but now allows the use of the term.

But the Turkish government, and some US historians, say the Armenian deaths and deportations should not be labeled genocide. They argue that the violence and upheavals came in the context of a war that brought great loss of life on all sides, and that the killings were a response to a massive armed rebellion by Armenians that began before the war broke out.

"There was killing on both sides and both sides have suffered. . . . But what happened does not fit the definition of genocide," said Narguiz Abbaszade, executive director of the Assembly of Turkish American Associations.

In the suit, Schechter, Griswold and the other plaintiffs, which include the Assembly of Turkish American Associations, argue that those views should be made available to the state's high school students. Central to their case is the claim that the Department of Education had included other viewpoints on the Armenian genocide in its 1999 curriculum guide, then removed them under political pressure from Armenians and their supporters on Beacon Hill, including Senator Steven A. Tolman, who represents Watertown, home to many Armenians. That amounts to censorship, said Harvey Silverglate, the attorney who represents the plaintiffs.

"After having decided it was educationally suitable to include both sides, the Department of Education succumbed to political pressure from a legislator and censored it out," Silverglate said. "That is unconstitutional."

But Schechter, Griswold, and the other plaintiffs say they are not trying to take a position on how the events should be classified, much less add to Armenians' suffering.

"This is a censorship case, not a historical controversy," Silverglate said....