California’s sports betting legalization efforts got a major boost this week as a number of influential Native American tribes offered an olive branch to the state’s horseracing operators.

On Wednesday, a coalition of 18 California tribes – including the Agua Caliente Band of Cahuilla Indians, Pechanga Band of Luiseño Indians and Morongo Band of Mission Indians – filed papers for a 2020 ballot initiative that would amend the state’s constitution to permit land-based sports betting at tribal casinos and state racetracks.

The California Sports Wagering Regulation and Unlawful Gambling Enforcement Act would enable wagering by anyone 21 years or older, tax sports betting revenue at 10% and prohibit wagers on games in which any California college team is playing. The proposal would also allow tribal casinos to offer craps and roulette, expanding their current slots and card games offering.

California already has a sports betting legislative vehicle in the works, but that measure foresees a role for the state’s licensed cardrooms, with which the tribes have repeatedly fought over the cardrooms’ alleged infringement of the tribes’ monopoly over house-banked card games.