But teaching about controversial topics this school year has been particularly challenging, Martell and other education researchers acknowledged. Teachers are reporting witnessing racist and xenophobic views they did not know were so present in their schools. A high-school teacher from the state of Washington wrote in comments on the Teaching Tolerance survey: “In over 15 years of teaching high school, this is the first year that swastikas are appearing all over school furniture.” Or a student in the hall chanting, “White power.”

What she used to think was non-controversial to teach has changed, said Meghan O’Keefe, who has taught English for a dozen years in Chicago Public Schools.

“A lot of people have confused the rhetoric the president used to get elected with making it okay to express racist ideas again,” O’Keefe said. “A lot of people believe they have the right to be racist and that we have to honor that as a legitimate point of view.”

That kind of atmosphere makes her wary about introducing a unit on the alt-right, she said.

Teachers may be censoring themselves more than necessary when deciding what to teach, said Diana Hess, the dean of the School of Education at the University of Wisconsin-Madison. Educators should use current events to help students learn about authentic political controversy, said Hess, who co-authored The Political Classroom with Paula McAvoy.

Learning about the alt-right, for example, is a lesson in political literacy. Teachers should not ask students to decide whether the alt-right is a good thing, but they can teach how it came about and how it has affected the political system, Hess said.

At Brookline High School, Cawthorne and Leslie were aware of the boundaries they must follow when designing the alt-right unit—and, so far, they haven’t gotten any pushback in response to their decision to teach it.

“It’s not our job ethically to push kids to go against Trump. It’s not our job to indoctrinate,” said Cawthorne.

Cawthorne and Leslie developed a class period devoted to the alt-right as part of a larger unit on white identity. Before tackling the alt-right, they talked to students about the concept of white identity and white fragility, the idea that whites can get so overwhelmed with guilt about the state of racism in American society that they simply cannot and will not talk about race. They also talked about how the concept of whiteness and who is white has changed in America as various groups of immigrants—whether they were Jews, Italians, or Irish—went from being considered second-class citizens and essentially of another race to part of the white majority. There was a diversity of whiteness in the 19th century that has largely disappeared, Cawthorne told the students.

Discussions about the alt-right fit into lessons on the complexities surrounding just what it means to be white in America, the teachers said. To prompt nuanced discussion backed up by facts, they first gave students a news-article explainer about the alt-right, then pushed the students to describe what they thought followers of the alt-right believed. The students saw the movement as leaving out people of color and focusing on America as a country for whites. They viewed the alt-right as a way for white people to take pride in themselves when they feel they have been pushed aside.