A federal judge has temporarily blocked Minnesota’s first-in-the-nation law banning prediction markets just days before it was to take effect, the latest clash between President Donald Trump’s administration and states over who regulates operators such as Kalshi and Polymarket.

Monday’s decision is the latest setback for states trying to outlaw or regulate fast-growing prediction market platforms.

U.S. District Judge Katherine Menendez in Minnesota found that the U.S. Commodity Futures Trading Commission, Kalshi and Polymarket were likely to succeed in their challenge to the law and that letting it take effect would cause “irreparable harm” to the operators.

The law was scheduled to take effect Saturday. It would have made it a crime to create or operate prediction markets or help administer nearly any activity connected to one. The law will remain blocked while the lawsuit proceeds.

Kalshi, Polymarket and the Commodity Futures Trading Commission want the law permanently blocked and argue that federal law gives the CFTC exclusive jurisdiction to regulate the type of “event-contract transactions” offered by Kalshi and Polymarket.

States argue that the vast majority of the business on prediction market platforms is sports betting, which they are empowered to regulate, and that is completely different from the commodities and futures contracts that the commission has historically regulated.