The contentious proposal has turned Sen. Bernie Sanders and Gov. Gavin Newsom into adversaries at time when the party can least afford it. As national Democrats search for a unifying theme ahead of the fall’s midterm elections, a California proposal to levy a hefty tax on billionaires is turning some of the party’s leading figures into adversaries just when Democrats can least afford division from within.Vermont Sen. Bernie Sanders traveled to Los Angeles on Wednesday to campaign for the tax proposal, which has Silicon Valley in an uproar, with tech titans threatening to leave the state. Democratic Gov. Gavin Newsom is among its outspoken opponents, warning that it could leave government finances in crisis and put the state at a competitive disadvantage nationally.At an evening rally near downtown, Sanders told cheering supporters that the nation has reached a crisis point in which “massive income and wealth inequality” has concentrated power over business, technology, government and the media within the “billionaire class,” while millions of working-class Americans struggle to pay household bills.He said enactment of the proposed tax would show “we are still living in a democratic society where the people have some power.”“Enough is enough,” Sanders said to a pulse of applause. “The billionaire class cannot have it all. This nation belongs to all of us.”The senator, a democratic socialist, is popular in California — he won the 2020 Democratic presidential primary in the state in a runaway. He’s been railing for decades against what he characterizes as wealthy elites and the growing gap between rich and poor.