As California voters weigh in this fall on a pair of dueling propositions that would legalize gambling on sports, one of the measures has drawn the ire of public workers unions and cities, including San Jose, that are worried its passage could undercut a chunk of their budgets.

Proposition 26, which would clear the way for sports-betting at California’s tribal casinos, also includes a little-known provision that critics say could threaten the future of cardrooms, including more than a dozen in the Bay Area, such as Artichoke Joe’s in San Bruno, Oaks Card Club in Emeryville and San Jose’s Bay 101 and Casino M8trix.