Throughout the history of the United States, various topics have been censored and banned in education, including teaching about evolution, racism, sexism, sex education, and LGBTQ+ topics. Due to the federal system of the country being highly decentralized, states are delegated with much of the responsibility for administering public education, and it is often governments of the red states that have enacted such policies.
In 2021, bills were introduced in multiple state legislatures to restrict teaching certain concepts, including critical race theory (CRT) and sexism, in public schools. Bills were passed in 14 states, all of which had both Republican-majority legislatures and Republican governors. Several of these bills specifically mention "critical race theory" or single out the New York Times 1619 Project. CRT is only taught at a university level, though some lower-level curricula have reflected basic themes of CRT.
Other state-level efforts have involved state boards of education restricting the teaching of issues surrounding race and sex.
History
Some of the first evidence of censorship of school curriculum in the United States comes during the Civil War, when Southern textbook publishers removed material critical of slavery. After the Civil War, a vigorous movement from groups like the United Daughters of the Confederacy in the South promoted the Lost Cause of the Confederacy in schools. The movement censored any offending works and lead to "indoctrination of southern schoolchildren with aristocratic social values unchanged since the antebellum epoch."
During the 19th century's temperance movement, some school book publishers revised content to suit the anti-alcohol position.
In the 1920s, during the aftermath of World War I, conservatives across the country attempted to ban teaching on evolution. The Fundamentalist–Modernist Controversy brought a surge of opposition to the idea of evolution, and following the campaigning of William Jennings Bryan several states introduced legislation prohibiting the teaching of evolution. Legislators proposed more than 53 bills from 1922 to 1929 (twenty in state legislatures and two in Congress), five of which succeeded. Legislation was considered and defeated in 1922 in Kentucky and South Carolina, in 1923 passed in Oklahoma, Florida, and notably in 1925 in Tennessee, as the Butler Act. The American Civil Liberties Union (ACLU) offered to defend anyone who wanted to bring a test case against one of these laws. John T. Scopes accepted, and he started teaching his class evolution, in defiance of the Tennessee law. The resulting trial was widely publicized by H. L. Mencken among others, and is commonly referred to as the Scopes Trial. Scopes was convicted; however, the widespread publicity galvanized proponents of evolution. When the case was appealed to the Tennessee Supreme Court, the Court overturned the decision on a technicality (the judge had assessed the fine when the jury had been required to). Although it overturned the conviction, the Court decided that the law was not in violation of the First Amendment to the United States Constitution. The Court held:We are not able to see how the prohibition of teaching the theory that man has descended from a lower order of animals gives preference to any religious establishment or mode of worship. So far as we know there is no religious establishment or organized body that has its creed or confession of faith any article denying or affirming such a theory. — John Thomas Scopes v. The State 154 Tenn. 105, 289 S.W. 363 (1927)The interpretation of the Establishment Clause of the First Amendment up to that time was that Congress could not establish a particular religion as the State religion. Consequently, the Court held that the ban on the teaching of evolution did not violate the Establishment Clause, because it did not establish one religion as the "State religion." As a result of the holding, the teaching of evolution remained illegal in Tennessee, and continued campaigning succeeded in removing evolution from school textbooks throughout the United States.
One expert in the 1920s described the anti-vaccine movement as America's first modern culture war.
In the 1960s, some movements sought to remove racist and sexist material from school textbooks. Historian Jonathan Zimmerman stated that in the 1960s, "there were history textbooks in this country, including in the North, that still described slavery as a mostly beneficent institution devised by benevolent white people to civilize savage Africans."