California’s initiative process has sometimes been a boon to taxpayers—think Proposition 13, which checked the uncontrolled growth of property taxes. On other occasions, however, it has yielded some mighty boondoggles. Chief among these are the “boutique initiatives” advanced by celebrities and Silicon Valley billionaires to make themselves feel good or to advance pet political causes—think Proposition 10, Hollywood director Rob Reiner’s early-childhood-development measure that created a host of busybody commissions funded by cigarette taxes. Boutique initiatives usually come with boutique prices. Among the costliest is Proposition 39, a 2012 measure that hiked corporate taxes on out-of-state businesses to “create energy...