The justices denied Delaware's petition for judicial review without comment, leaving in place a ruling by the U.S. Third Circuit Court of Appeals in Philadelphia that limits sports betting in Delaware to multi-game, or parlay, bets on National Football League games.

The appeals court heard arguments last August on a request by the NFL and other sports leagues for an injunction to prevent Delaware from starting sports betting with the launch of the NFL season. But instead of ruling on the injunction, the appeals court turned directly to the leagues' claim that Delaware's proposal to allow single-game bets on a variety of professional and collegiate sports would violate a 1992 federal ban on sports wagering.

The court declared that the state's new sports betting lottery had to be similar to the betting scheme used in a failed 1976 National Football League lottery that allowed Delaware to be one of only four states to receive grandfathered exemptions from the federal ban.

The ruling stunned attorneys for the state, who were not given the opportunity to defend the merits of the sports betting proposal. Gov. Jack Markell subsequently approved an appeal to the Supreme Court that was funded by Delaware's three slot-machine casinos, which have exclusive rights to offer sports betting.