California Gov. Gavin Newsom proposed a tax on America’s billionaires — while remaining in steadfast opposition to the very same levy on the wealthiest in his state. After California’s own billionaires tax was approved for the November ballot, Newsom announced Friday that he supports a national billionaires tax “that ensures the people at the very top pay at least the tax rate their own workers pay.” Newsom has long opposed the proposed California measure, which would hit the state’s wealthiest with a 5% tax to cover healthcare costs in the state. He failed to broker a last-minute deal to keep...