It’s the 50th anniversary of the 1964 Civil Rights Act, and many today would make the case that civil rights are a concern of the 20th century. We live in a post-racial society, this line of reasoning goes, and we’ve learned from our mistakes.

Unfortunately, recent news from the U.S. Supreme Court shows that these concerns are all too modern, and that the country and its higher education institutions are still divided on issues such as affirmative action.

In a 6-2 decision, the court upheld a Michigan voter initiative to ban racial preferences in the admissions process of the state’s public universities, overturning a 2012 circuit court ruling that said the initiative was a violation of the Constitution’s equal-protection clause.

In delivering the majority opinion, Justice Anthony Kennedy said the court did not have the power to overturn the initiative.

“There is no authority in the Constitution of the United States or in this court’s precedents for the judiciary to set aside Michigan laws that commit this policy determination to the voters,” Kennedy wrote.

This decision, though not a rebuke of affirmative action itself, nonetheless leaves states able to reject the policy outright, a dangerous precedent to set. Affirmative action ensures students have experience with diversity in college, which research shows is important for citizens of healthy democracies and an increasingly globalized world.

For example, A 2011 Notre Dame study examined three different aspects of campus diversity: more students of color, diversity-related curriculum, and interactions with peers of other races, and found these experiences were associated with an increase in civic growth.

However, the greatest benefits came when the experiences were not seen as structured, but as interpersonal interactions with racial diversity. The researchers said the findings provided “solid evidence for the benefits of diversity experiences.”

Without affirmative action, these experiences will be harder to come by. But diversity is not just something to be sought for a healthy citizenry overall. Though racial quotas have previously been frowned upon by the courts, a policy that takes race into account isn’t unduly discriminatory. It’s a correction.

Our country’s checkered past on civil rights has left many people of color in a cycle of poverty and lack of opportunity, and education is the key to breaking that cycle. Policies such as affirmative action help correct long-standing social wrongs, evening the playing field for those that have not had the same chances.

Opponents of race-based affirmative action often argue for an income-based program of the same type. While such a policy would help correct class disparities on college campuses, such a program would undermine the goal of increased diversity and could lead to pernicious stereotypes.

As much as we would like to believe it, we do not live in a “post-racial” society. The ramifications of post Civil Rights Act discrimination are less visible than segregated schools and Jim Crow laws, but they do have a creeping homogenization effect on our campuses and communities. Without affirmative action, college students could go through their entire educational career without these critical experiences with students unlike themselves, and without affirmative action, cycles of poverty will continue to be perpetuated. Fifty years after outlawing legalized prejudice, the Supreme Court’s decision has made it clear that states are free to turn back the clock on campus diversity.