Cabazon Band Uses Sworn Declarations to Show Kalshi Bets on Tribal Land
A tribe that bans on-reservation sports betting told the justices its own officials were able to wager anyway.
The Cabazon Band of Cahuilla Indians has put a concrete factual claim before the U.S. Supreme Court in the prediction market dispute: that people, including tribal officials, can place sports event-contract bets through the Kalshi app while physically present on the Band's reservation, even though the tribe prohibits sports betting there. The Cabazon Band's amicus brief, filed October 6, supports New Jersey's petition for review of the Third Circuit's decision in KalshiEX v. Flaherty (Docket No. 26-299), and its reliance on sworn declarations distinguishes it from briefs that rest mainly on legal argument.
What the Cabazon Band told the Court
According to a summary of the filings published by Pillsbury, the Band prohibits on-reservation sports betting. Tribal officials nonetheless used sworn declarations to demonstrate that they could place bets through the Kalshi app on the reservation. The Band's position is that this undermines a tribe's authority to decide whether sports wagering takes place on its own land, which is the core regulatory choice the Indian Gaming Regulatory Act (IGRA) leaves to tribes and states through the compacting process.
The brief also frames the issue as one of fairness and revenue. Gaming revenue, the amici argue, is meant under IGRA to flow primarily to tribes, where it funds health care, housing, education and public safety. They also point to the regulatory burden tribes carry: the filings cite more than $450 million a year in tribal spending on gaming regulation and more than 6,000 tribal regulators, in contrast with Kalshi's position that it answers only to the Commodity Futures Trading Commission. Two days later, on October 8, 130 federally recognized tribes and 15 tribal organizations filed a separate amicus brief supporting review. For background on that filing, see our report on tribal nations asking the Supreme Court to review Flaherty v. Kalshi.
Why evidence of on-reservation access matters
The Cabazon name carries history in Indian gaming. California v. Cabazon Band of Mission Indians, decided in 1987, helped establish the legal foundation on which Congress built IGRA in 1988, and the Pillsbury summary cites it as background on tribal sovereignty. Our explainer on the history from Cabazon to IGRA traces that line. The Band's present role is a notable continuity: the tribe whose litigation shaped the statute is now offering evidence that a federally regulated financial product can reach inside a tribal jurisdiction that has chosen not to permit sports wagering.
Sworn declarations serve a specific purpose in this setting. Prediction market operators have generally argued that the contracts are swaps or investment trading governed exclusively by federal commodities law, not gambling. A declaration that a person stood on tribal land, opened the app and placed a sports contract is not a legal conclusion, but it supplies a fact pattern the Court can weigh when asking where a transaction occurs. The Ninth Circuit, in its September 16 opinion in Blue Lake Rancheria v. Kalshi, treated a customer's participation from tribal land as enough to bring the transaction within IGRA, as described in coverage by Covers. Our summary of that decision is in the Ninth Circuit Blue Lake Rancheria ruling report.
A circuit split and a pending petition
The Pillsbury summary notes that the Third Circuit's decision, which held that federal commodities law likely prevents New Jersey from applying its gaming laws to Kalshi's sports event contracts, conflicts with rulings from the Ninth and Sixth Circuits. That conflict is the kind of disagreement the Supreme Court considers when deciding whether to grant review, though the Court has complete discretion. The same summary reports that three certiorari petitions are pending, and it does not say whether the Court has acted on this one. Readers unfamiliar with how such petitions are evaluated can consult our explainer on how the Supreme Court decides tribal gaming cases.
The tribes also argue that timing matters. Ordinarily, a question like this might be resolved in a case to which tribes are parties. The amici say uncertainty itself is harmful because it makes it hard to plan gaming investments. The industry they describe is large: nearly 250 tribal governments operating gaming facilities in 29 states, producing more than $46 billion in gross gaming revenue in fiscal year 2025, according to the figures cited in the filings.
What to watch
Several points will determine how much weight the Cabazon evidence carries. The first is whether the Court grants review. The second is whether any eventual decision turns on where a transaction is deemed to occur, which is the question the declarations speak to, or on whether commodities law displaces state and tribal authority altogether. A third is whether other tribes with their own sports betting prohibitions develop similar records. This article reports the content of the filings as summarized by others; it does not assess the underlying merits, which the parties dispute. Operators and states, including New Jersey, are advancing the opposing legal view that federal law governs these contracts. Background on the federal-tribal framework is available in the Legal Guide, and the California state hub lists tribes in the state where the Cabazon Band is located.