LOS ANGELES — The most expensive ballot proposition bet in U.S. history went bankrupt on Tuesday as California voters overwhelmingly rejected sports betting, shooting down initiatives by Native American tribes and the betting industry.

The two groups have raised nearly $600 million in competing efforts to grow the game and capture a share of a potential billion-dollar market in the nation’s most populous state. But voters didn’t want a piece of that action.

Proponents and opponents of the dueling measures flooded voters with an explosion of ads over proposals that would have legalized sports gambling by allowing it in tribal casinos and racetracks or via mobile and online betting.

Money raised and spent more than doubled the record amount deployed in 2020 by Uber, Lyft and other app-based transportation and delivery services to prevent drivers from becoming eligible employees for benefits and protections employment.

Still, pre-election polls showed both ballot measures faced an uphill battle to win a majority. More than 30 other states allow sports betting, but gambling in California is currently limited to Native American casinos, racetracks, card rooms, and the state lottery.

Proponents of both initiatives proposed different ways to offer sports betting, and each touted other benefits they said would accrue to the state if their measure were approved.

Proposition 26 would have allowed casinos and the state’s four major racetracks to offer in-person sports betting. The initiative funded by a coalition of tribes would also have allowed roulette and dice games in casinos. A 10% tax would have helped pay for gambling law enforcement and programs to help drug addicts.

Proposition 27 would have allowed online and mobile sports betting for adults. The big game companies should have partnered with a tribe involved in the game or the tribes could have entered the market on their own. The move was backed by DraftKings, BetMGM and FanDuel – the latter of which is the official odds provider for The Associated Press – along with other national sportsbook operators and a few tribes.

The initiative was being promoted for the funding it promised to channel through tax revenue to help the homeless, the mentally ill and the poorer tribes who have not been enriched by the casinos.

The Office of the Nonpartisan Legislative Analyst found that both initiatives would have increased state revenue, but it was unclear by how much. Proposition 26 could have made tens of millions of dollars while Proposition 27 could have generated hundreds of millions, the bureau said.

However, these revenues could have been offset if people spent money on sports betting instead of shopping or buying lottery tickets. Democratic Gov. Gavin Newsom took no position on either proposal, but said Proposition 27 was “not a homeless initiative.”

The California Republican Party opposed both proposals. State Democrats opposed Proposition 27 but were neutral on Proposition 26. Major League Baseball supported Proposition 27.

The No on Prop 26 campaign, funded largely by card rooms who stood to lose, said the measure would have given a handful of wealthy and powerful tribes “a virtual monopoly on all gambling in California”.

The No on 27 committee said the proposal was based on misleading promises and said the game companies behind it “didn’t write it for the homeless, they wrote it for themselves”.