This conflict of interest poses huge ethical risk for Supreme Court

In a letter sent to U.S. Supreme Court Chief Justice John Roberts on June 30, Rep. Greg Landsman (D-Ohio) sounded the alarm about "conflicts of interest and ethical risks posed by prediction market betting on Supreme Court decisions and Court operations." And the Democratic congressman urged Roberts to "consider adopting a policy to ban the use of prediction markets for all justices, officers, and staff."

Landsman isn't the only one who is speaking out about prediction markets and the High Court. In Above the Law, Senior Editor Kathryn Rubino argues that prediction markets need to be addressed much more "explicitly" than what one presently finds in the High Court's "existing code of conduct."

"Prediction markets have exploded," Rubino explains in Above The Law. "Monthly trading volume on Kalshi and Polymarket ballooned from under $5 billion in September 2025 to roughly $24 billion by April 2026. And the contracts available aren't exactly abstract. Users were able to bet on the outcomes of cases like birthright citizenship, whether states can count mail-in ballots after Election Day, the president's ability to fire members of independent agencies, and transgender athlete participation in high school sports. They can also bet on whether and when a specific justice will retire, and who their successor might be."

Rubino continues, "That's a menu that would be very interesting to someone who already knows the answers. Justices know how they're voting before opinions are released. Law clerks know how cases are coming out. Judicial assistants know when a retirement is imminent. The insider information advantage here isn't theoretical — it's structural, and it accrues to a specific, small group of people at One First Street NE."

The Above the Law reporter points out that "technically," the Code of Conduct for Justices covers prediction markets. But according to Rubino, Landsman, in his letter to Roberts, "makes the case that technically-already-prohibited isn't enough — partly because the prohibition isn't explicit, and partly because the conflict-of-interest risk isn’t limited to obviously case-related bets."

"This Court has demonstrated a fairly consistent approach to outside calls for ethics reform: acknowledge them minimally, act on them minimally, and wait for the news cycle to move on," Rubino writes. "A letter from a Democratic member of the minority, however well-reasoned, is not historically the kind of thing that moves Roberts to act with urgency. The Court's ethics problem is not going to resolve itself."

Rubino continues, "If Roberts is looking for a genuinely easy win — a way to get ahead of a problem before it metastasizes into a scandal rather than reacting to one after the fact — this is a fairly painless place to start. All he has to do is say the obvious thing. But um, I wouldn't hold your breath."