The ballot proposition to legalize sports betting in California was rejected by Californian voters on Tuesday. The measure, supported by the most expensive campaign in U.S. history, had insufficient support as voters expressed concerns about the gambling impact on the community.

Voters rejected sports betting propositions:

In the most populous state, more than 4.6 million voters rejected Proposition 26 and Proposition 27 which would have allowed casinos and the state’s four horse tracks to offer sports betting in person and, respectively, mobile and online gambling.

Less than 30% of voters supported Proposition 26, while the mobile and online gambling proposition had only 16% support from Californian voters.

Voters’ concerns:

According to AP, voters who rejected in-person sports betting ” did not want to enrich wealthy tribes who would get a virtual monopoly on gambling,” as gambling in California is currently limited to Native American casinos, horse tracks, card rooms, and the state lottery.

Voters also rejected Proposition 27 as they expressed concerns that massive gambling expansion may increase the number of addicts and tout children to place bets on devices:

“Our internal polling has been clear and consistent for years: California voters do not support online sports betting,” said Anthony Roberts, tribal chairman of the Yocha Dehe Wintun Nation. “Voters have real and significant concerns about turning every cellphone, laptop, and tablet into a gambling device, the resulting addiction, and exposure to children.”

Billion-dollar market:

The gaming industry largely supported the measure in an attempt to expand gambling and take advantage of the potential billion-dollar market. With $600 million raised, the initiative became the most expensive one in U.S. history due to the extensive advertisement and promotion activities aimed at voters of the nation’s most populous state.

National sports betting operators, including DraftKings, BetMGM, and FanDuel backed the initiative. They offered to funnel tax revenues to help the homeless, the mentally ill, and poorer tribes that haven’t been enriched by casinos. A few Native American tribes also supported the measure to legalize their tribal casinos claiming that sports betting could bring a 10% tax revenue to enforce gambling laws and rehab programs for addicts.

According to the independent Legislative Analyst’s Office, Proposition 26 could bring in tens of millions of dollars while Proposition 27 could bring in hundreds of millions.

Democratic Gov. Gavin Newsom didn’t take a position, 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.