Just days after a teenager unfurled a Confederate flag at a high school football game in Howard County, Md., teachers began reworking lesson plans to discuss the student’s display and the school’s decision to discipline him.

Their talking points: What is free speech? How is the action different from the landmark U.S. Supreme Court decision that allowed several students to wear black armbands in protest of the Vietnam War? What does the flag represent? Why does it mean such different things to different people?

“It felt like a good time to talk about the issue,” said Callie Casper, a government and human geography teacher at River Hill High School. “Some kids wanted to talk about it, sometimes I brought it up.”

Teachers across the country routinely must delve into racially sensitive topics such as the display of the Confederate flag and the recent killing of an unarmed black teenager in Ferguson, Mo. They also tackle politically charged subjects such as same-sex marriage and immigration reform. It is a fine line to walk, they say, as they try not to offer their own personal views while provoking critical thinking about the issues everyone is talking — and tweeting — about.

“It is a part of what social studies teachers do. They address topics as they come up naturally through class discussion, related to current events, and as a part of the curriculum,” said Mark J. Stout, a curriculum coordinator for the Howard County Public School System. Stout sent an e-mail to social studies teachers in the school district to discuss lesson plans around the Confederate flag incident. Stout included the school system’s policy on teaching controversial issues, the superintendent’s statement calling the flag a “powerful symbol of racism, hatred, and unspeakable acts against humanity” and news articles.

A Confederate flag is seen on I-95 between Quantico and Fredricksburg this summer. The flag, often seen as a symbol of racism, is one the subjects that can be hard to address in classrooms. (Yue Wu/The Washington Post)

A sign hanging on the door of Billy Shulman’s classroom at Northwestern High School in Prince George’s County acknowledges that thorny issues will come up in class and dictates how he envisions the discussions will take place, free of conflict.

“Thank you for leaving your prejudice and ignorance outside of the classroom,” reads the sign, which has been a part of his government class for several years.

Shulman said he tackles gay marriage as a lesson about civil rights. With many immigrants from African and Central American countries, Shulman said, he has found same-sex marriage to be a difficult topic because of the negative views some students bring with them to class.

“I tell these kids from day one that I’m not trying to change your mind,” Shulman said. “I don’t do a lot of debates. I like to discuss.”

He asks students: Why do you have this perspective? What experience do you have to have this view?

“It is very hard because I don’t want to preach my views, but I don’t want students to put down people who may be affected by these issues,” Shulman said. “So it is a fine line; a lot of it has to deal with creating a certain environment in the classroom.”

Casper said she discussed Civil War history as she talked to her students — many of whom were offended by the Confederate flag, but most of whom were confused as to why someone would display it — about the meaning of the flag. She said she asked the students what it means to the state of Maryland? They said some parts of Maryland were Confederate and some where Union.

“Why would it be an issue here?” she asked.

“It’s a sign of hate,” one student responded.

Casper said she asked her class if they would be surprised to hear that some people don’t view it that way.

She recalled teaching U.S. history at a Winchester, Va., high school, where students would have Confederate flags on their cars and wear belt buckles with symbols of the flag. Students there said the flag was a representation of their Southern heritage, Casper said, adding that the district routinely struggled with how to respond.

“The superintendent would never have made a statement about it,” she said. And so, she said, her Howard County class talked about the regional differences and how students who live 90 minutes southwest can have different views.

Patrick Kelly, who teaches Advanced Placement U.S. government classes at Bythewood High School in Columbia, S.C., said he doesn’t whitewash racially sensitive lessons. He often uses supplemental materials, noting that “textbooks can’t keep up. One written this year has no idea what ISIS is.”

During a recent lesson about the Jim Crow era, Kelly read from “Trouble in Mind” by Leon F. Witwack, who offers a vivid description of a lynching. Kelly said he could hear a pin drop in the class.

Earlier this year, an elementary school in Prince George’s canceled a skit about immigration reform after a parent complained that the material, called “The Uninvited Guest,” was offensive to immigrants.

In the skit that was taught to a third-grade class, Uncle Sam berates a visitor who comes in through a window, uninvited, telling him to go back to where he came from. “I don’t want any drug addicts or drug traffickers to come in either. No criminals. We have enough problems; we don’t need to invite more!”

The skit prompted the school district to take a closer look at supplemental items, which are widely available on the Internet.

Kelly said while he is always willing to bring current events into his classroom discussion, there are times when he limits it. He said, for example, a student mentioned the protests in Ferguson during a discussion about trust in government.

“Ferguson then became a point of reference,” he said. Kelly used it as a case study of what can happen in a society when trust breaks down. The conversation stopped short of the killing of Michael Brown, the unarmed teenager.

“That’s the kind of thing we steer away from,” he said. “I don’t want to go down that path. Emotions are very raw.”

Pamela King-Williams, a parent in Prince George’s, said she thinks shying away from discussing what happened to Brown and others who have captured headlines in recent years does a disservice to students.

She would routinely ask her daughter if teachers would talk about it. She said her daughter said they didn’t.

“It needs to be talked about in the classroom,” she said. “Our kids would be better educated and have a true understanding rather than what they are seeing on Twitter or Facebook.”