In a historic commencement address at Howard University on June 4, 1965, President Lyndon Johnson laid out the intellectual and moral basis for affirmative action. Speaking less than a year after the passage of the Civil Rights Act and two months before the passage of the Voting Rights Act, he invoked a metaphor that remains resonant nearly 60 years later: “You do not take a person who, for years, has been hobbled by chains and liberate him, bring him up to the starting line of a race and then say, ‘You are free to compete with all the others,’ and still justly believe that you have been completely fair.”

Heeding Johnson’s call and responding to the demands of the civil rights movement for racial justice, many selective colleges and universities altered their admissions policies with the express intent of increasing the number of Black students. The need for change was undeniable: As late as 1960, just 15 students (0.5 percent) of the combined entering classes at Harvard, Yale and Princeton were Black. At the U.C.L.A. School of Medicine, which, like other University of California institutions, followed an official policy of colorblindness, not a single Black person was among the 764 students who received M.D.s from 1955 to 1968. Among people in the legal profession as a whole, including graduates of the five historically Black law schools, fewer than 1 percent were Black in 1968. Affirmative action offered a way to take into account far-reaching differences in personal circumstances and to begin to right a historic wrong.

After a brief honeymoon of public support, affirmative action was met with a powerful backlash, and the policy has been under attack ever since. Decades of lawsuits and legislation have chipped away at the use of racial preferences. And now, in a 6-to-3 decision, the Supreme Court has consigned them to the grave.

The intensity and duration of the attack are sad confirmation that many Americans remain unwilling to reckon with the barbarity of our racial history. Every period of progress for Black people has been met with a racial backlash. In response to Reconstruction, Southern white people developed an entirely new and mythical history of slavery, the Civil War and ultimately Reconstruction. More than a century later, this insistence on denying history lives on. Witness the laws in a growing number of conservative states that prohibit teaching the truth about racial oppression, with dismissal and possibly even jail for teachers who dare to defy them.

Affirmative action was at best a modest form of recompense for centuries of exploitation and exclusion — far short of the reparations favored by more than three in four Black Americans. But it produced important gains: greater Black representation in elite colleges and professional schools, a growing African American middle class and more members of minorities in positions of leadership in key institutions. Affirmative action’s elimination is a monumental setback for racial justice. It will most likely lead to a substantial decline in racial and ethnic diversity at our leading colleges and universities and over time will narrow the pipeline that has led to a more diverse — and representative — leadership class.

Almost immediately, it was the reparative element of affirmative action that provoked the most passionate opposition. As early as 1970, a leading policy journal, The Public Interest, ran an article denouncing what critics said were quotas at Yale Law School. The following year, The New York Times published an opinion essay by the eminent philosopher Sidney Hook claiming that the federal government was pressuring institutions of higher education to discriminate against qualified applicants. By 1972, the charge of reverse bias was published in The Wall Street Journal and elsewhere and then fully elaborated in Nathan Glazer’s influential book, “Affirmative Discrimination.”