The clash between a leading prediction-market company and a pivotal swing state could offer a preview of the next major battle between state governments and this fast-growing industry.

“I was sitting at my desk when Twitter suddenly started showing a flood of notifications,” said Jacobs, whose screen filled with posts from Kalshi employees, lawyers and other supporters. “My reaction was: Wow, they are really angry,” she said.

Jacobs was surprised by what had triggered the outrage: a commission notice informing voters that they could not bet on an election in which they were casting a ballot. According to the commission, placing such a wager could invalidate a ballot or even lead to a referral to state prosecutors.

Jacobs said the notice merely stated the basic provisions of a Wisconsin election law originally enacted in 1849.

“You cannot vote if you have been convicted of a felony and remain under active supervision. You cannot vote at 17, and betting on an election in which you vote is the same: it is not allowed,” she said.

Fast-forward to 2026, and Kalshi—the company at the forefront of the prediction-market boom—is attacking the law as “insane,” “illegal” and a form of “voter suppression.”