In Loudoun County, Va., a group of parents led by a former Trump appointee are pushing to recall school board members after the school district called for mandatory teacher training in “systemic oppression and implicit bias.”

In Washington, 39 Republican senators called history education that focuses on systemic racism a form of “activist indoctrination.”

And across the country, Republican-led legislatures have passed bills recently to ban or limit schools from teaching that racism is infused in American institutions. After Oklahoma’s G.O.P. governor signed his state’s version in early May, he was ousted from the centennial commission for the 1921 Race Massacre in Tulsa, which President Biden was visiting on Tuesday to memorialize one of the worst episodes of racial violence in U.S. history.

From school boards to the halls of Congress, Republicans are mounting an energetic campaign aiming to dictate how historical and modern racism in America are taught, meeting pushback from Democrats and educators in a politically thorny clash that has deep ramifications for how children learn about their country.

Republicans have focused their attacks on the influence of “critical race theory,” a graduate school framework that has found its way into K-12 public education. The concept argues that historical patterns of racism are ingrained in law and other modern institutions, and that the legacies of slavery, segregation and Jim Crow still create an uneven playing field for Black people and other people of color.

Many conservatives portray critical race theory and invocations of systemic racism as a gauntlet thrown down to accuse white Americans of being individually racist. Republicans accuse the left of trying to indoctrinate children with the belief that the United States is inherently wicked.

Democrats are conflicted. Some worry that arguing America is racist to the root — a view embraced by elements of the party’s progressive wing — contradicts the opinion of a majority of voters and is handing Republicans an issue to use as a political cudgel. But large parts of the party’s base, including many voters of color, support more discussion in schools about racism’s reach, and believe that such conversations are an educational imperative that should stand apart from partisan politics.