California’s titans are gearing up for what’s sure to be an outrageously expensive clash over a proposed wealth tax on residents worth more than $1.1 billion. Supporters say they have more than enough signatures to put their ballot measure before voters in November; opponents say they do too for two measures that would override it. Tens of millions of dollars have already been spent on various campaigns, with some of the most eye-popping sums coming from tech founders, such as Google’s Sergey Brin.
But whether California’s wealthiest residents end up having to fork over more of their money to ...