Historians Gillian Frank and Adam Laats write in Slate about the long history of suppressing textbooks that discuss race and class and investigating or firing teachers who veer away from the standard patriotic view of American history.

They describe the classic story of the textbook series written by progressive educator Harold Rugg of Teachers College, Columbia. Rugg wanted students to learn about the social, economic and political problems of contemporary society in the 1930s. His books were widely adopted but fell victim to a rightwing campaign that labeled them as socialist or Communist, which they were not. The campaign was successful, and the Rugg books were ousted from classrooms across the nation.

The authors tie the current efforts to ban critical race theory (taught in law school) and The 1619 Project from being taught in schools to this long tradition of avoiding controversial subjects.

There is an even longer tradition…