The measure that passed unanimously by voice vote Thursday was written as a change to the Senate’s rules, so it will go into effect immediately. It comes a week after a U.S. special forces soldier was charged with using classified information to bet on the January capture of Venezuela’s then-president, Nicolas Maduro, and as lawmakers increasingly voice concerns about who might be making public wagers on the war with Iran.

“United States senators have no business engaging in speculative activities like prediction markets while collecting a taxpayer-funded paycheck, period,” said Sen. Bernie Moreno, R-Ohio, who sponsored the resolution. An amendment by Sen. Alex Padilla, D-Calif., broadened the measure to include staff.

Senate Minority Leader Chuck Schumer, D-N.Y., said the move was a “no-brainer.” He encouraged the House and Trump administration to do the same.

“We must never allow Congress to turn into a casino where members representing the public can gamble on wars or economic crises or elections,” Schumer said. “That would destroy the very principle of representative government.”

Sens. Todd Young, R-Ind., and Elissa Slotkin, D-Mich., have introduced a bill to ban all federally elected officials and government employees from using insider information to make prediction market bets. Young said the resolution was “a good first step” and he encouraged the Senate to take up their bill.

Prediction markets, including the betting platform Polymarket and its chief rival Kalshi, have come under scrutiny as the business has expanded. Polymarket has received particular criticism as a venue for offshore trades that are beyond the reach of U.S. regulators.

Earlier this month, The Associated Press reported that a group of new accounts on Polymarket made highly specific, well-timed bets on whether the United States and Iran would reach a ceasefire on April 7, resulting in hundreds of thousands of dollars in profits for the new customers. On the same day the AP published the report, the White House warned staff against using private information to trade on prediction markets.

The administration has been a key ally of the growing prediction market industry in a legal fight with states seeking to ban the platforms. Donald Trump Jr., the president’s eldest son, is an adviser for both Polymarket and Kalshi. Trump’s social media platform Truth Social is also launching its own cryptocurrency-based prediction market called Truth Predict.

“The whole world, unfortunately, has become somewhat of a casino, and you look at what’s going on all over the world and Europe and every place, they’re doing these betting things,” Trump said this month.