One of the nation’s largest teachers unions on Tuesday vowed to defend members who are punished for teaching an “honest history” of the United States, a measure that’s intended to counter the wave of states seeking to limit classroom discussion on race and discrimination.

In a virtual address to members of the American Federation of Teachers, president Randi Weingarten said the union is preparing litigation and has a legal defense fund “ready to go.” She promised to fight “culture warriors” who attempt to limit lessons on racism and discrimination by labeling it as critical race theory.

At least six states have passed new laws limiting how race can be taught in the classroom, including Florida, and similar proposals are being considered in more than a dozen others. Many of the bills are intended to bar the teaching of critical race theory, an academic framework that examines history through the lens of racism. It centers on the idea that racism is systemic in the nation’s institutions and that they function to maintain the dominance of white people in society.

Bills in some states threaten to fine individual teachers who violate the rules or reduce state funding to their schools.

“Mark my words: Our union will defend any member who gets in trouble for teaching honest history,” Weingarten said in her address. “Teaching the truth is not radical or wrong. Distorting history and threatening educators for teaching the truth is what is truly radical and wrong.”

In an interview, Weingarten said the union is adding $2.5 million to an existing legal defense fund in anticipation of local fights over the teaching of race. The funding will be used to defend teachers who are disciplined for teaching about slavery and racism. The union is also considering filing lawsuits to get clarification about new state laws limiting how racism can be discussed in schools, she said.

“We’re looking at these laws to see if courts will give some clarification in advance,” Weingarten said. “It just looks like it’s an attempt to erase so much of the history of the United States.”

Once an obscure academic idea, critical race theory has become a political rallying cry for Republicans who argue that it sows division and makes children feel guilty for being white. But Weingarten said the concept has mostly been taught at the college level and is not taught at the nation’s elementary, middle and high schools.

Instead, she says conservatives are invoking the theory to bully teachers and prevent any critical discussion of the nation’s history. Some of the state laws are so expansive, she said, that they appear to prevent any accurate lesson on the Civil War, slavery or its abolition.