The high-stakes showdown over a proposed wealth tax is intensifying in California, pitting progressive firebrand Sen. Bernie Sanders (I-VT) and a healthcare union against Gov. Gavin Newsom (D-CA) and a coalition of business titans and cryptocurrency executives.

Sanders is set to rally supporters in downtown Los Angeles on Wednesday afternoon, casting the “billionaire tax” as a basic question of economic fairness and urging voters to make billionaires pay more. The Vermont senator, a democratic socialist, is extremely popular in the state and has drawn thousands of people out before. Though he’s a millionaire himself, he has been fighting against the wealth gap for decades.