On March 25, 1965, at the conclusion of the brutally consequential march from Selma to Montgomery, Martin Luther King, Jr., delivered a speech titled “Our God Is Marching On!” He spoke to a crowd of twenty-five thousand people on the grounds of the Alabama state capitol, in view of the office window of the segregationist governor George Wallace. The address is not among King’s best-known, but it is among the most revelatory. King argued that, in the decade since the bus boycotts in that city, a new movement had emerged and an older order was starting to fall away. Referring to the historian C. Vann Woodward’s book “The Strange Career of Jim Crow,” King said that racial segregation had begun not simply as an expression of white supremacy but as a “political stratagem employed by the emerging Bourbon interests in the South to keep the southern masses divided and southern labor the cheapest in the land.” The so-called split-labor-market theory held that, by creating a hyper-exploited class of Black people, white élites could hold down the wages of white workers. And so racism didn’t just injure Black people, its immediate object; it took a toll on white laborers, too.

The Montgomery speech is notable because it presages the interracial populism that became an increasingly prominent part of King’s thinking and organizing in his remaining years; it’s notable, too, because it highlights the extent to which his thought had always been informed by a study of American history. In his “I Have a Dream” speech, he had mentioned the ideas of “interposition and nullification,” which he attributed to Wallace, but which implicitly harked back to John C. Calhoun’s efforts to protect slavery. King’s final book, “Where Do We Go from Here?” (1967), rooted an argument for a universal basic income and general economic redistribution in the Homestead policies of the mid-nineteenth century. To an underappreciated extent, he related the nation’s contemporary concerns to a genealogy of past ones.

Such historical continuities stand to be lost in the mainstream American understanding. Legislation recently passed in eight states—a list that may expand—seeks to restrict what students can be taught about our past, segregating laudatory and thereby permissible subjects in American history from a Jim Crow section in which the nation’s deepest shortcomings are hidden from view. These efforts come at a fraught moment. Last week, when President Joe Biden spoke to the nation from National Statuary Hall on the anniversary of the January 6th insurrection, he pointed out that the riot brought the Confederate flag into the halls of Congress—a violation that had not occurred even during the Civil War.

The substance as well as the symbols of a divided era have been infiltrating our political spaces. “In state after state, new laws are being written not to protect the vote but to deny it, not only to suppress the vote but to subvert it,” the President observed. King’s speech at the Alabama capitol, it should be recalled, was given amid a fight for a voting-rights law. Stripping the right to vote from Black Southerners, King noted, laid the groundwork for laws that further disadvantaged poor people across racial lines. Then as now, Southern legislatures justified limiting the franchise with specious claims about electoral malfeasance.