Sign up for Executive Dysfunction, a newsletter that highlights one under-the-radar story each week about how Trump is changing the law—or how the law is pushing back. You’ll also receive updates on the latest from Slate’s Jurisprudence team.

Less than one lifetime ago, courageous protesters—Black women and men—were brutally attacked on Edmund Pettus Bridge by police officers with tear gas and billy clubs. These protesters sacrificed their own safety to secure something deemed even more sacred: their right to vote. The fruit of that sacrifice was the historic Voting Rights Act of 1965.

Yet on April 29, the Supreme Court’s landmark decision in Louisiana v. Callais dramatically narrowed how Section 2 of the Voting Rights Act operates. What’s been less discussed than the significant consequences of the ruling is how the majority’s reasoning rests in substantial part on the premise that colorblind rules and practices produce fairer outcomes. That colorblindness promotes justice. But this premise is wrong.

To understand why, imagine a scenario with no historical discrimination and fully colorblind policies. Would colorblindness in this setting, a setting presumably most favorable for just outcomes, be fair? My economics research published in the peer-reviewed Journal of Law and Economics demonstrates that the answer is a definitive no. I demonstrate mathematically that with an otherwise level playing field, when one group is larger, its members systematically enjoy more connections—along with the opportunities that flow through them. This applies predictably to both the protections of affirmative action and voting rights laws that the court in recent years has hollowed out.

Call the phenomenon itself “social network discrimination.” It emerges not from malice, but from math.

Consider a simple example in the employment context with three trusted employees providing referrals for potential job candidates. The employees have equal qualifications, the company does not use race in hiring, and initial hiring is fair. In this hypothetical, one-third of the population is minority, and so one-third of employees are also minorities. Each employee interacts with each of nine prospective job applicants at a professional event, and later makes........

© Slate