The Supreme Court may be more likely to bite if federal appeals courts draw opposite conclusions. The industry is closely watching the Ninth Circuit, whose judges have so far appeared more skeptical of federal preemption than the Third Circuit’s.

States and tribes say that prediction markets offer gambling, so they should fall under their jurisdiction (and comply with their laws). Selig has sided with prediction markets by arguing that users are really trading event contracts, which should make the CFTC “the exclusive regulator.”

McCormick and Gillibrand’s bill, if passed, would strengthen Selig’s case by building out the CFTC’s role. A different bipartisan proposal from Sens. Adam Schiff, D-Calif., and John Curtis, R-Utah, would push back on it by banning prediction markets from offering wagers on sports.

Meanwhile, the House could soon follow the Senate in blocking its members and their staff from using prediction markets. A spokesperson for House Minority Leader Hakeem Jeffries, who said earlier this year that it would be “reasonable for us to take a look at what can be done in this space,” told Semafor he was generally supportive of the Senate’s push.

Nicholas Wu contributed reporting.