One of the main themes in the blockbuster case of Janus v. AFSCME—currently before the United States Supreme Court—is the risk of having unions sit on both sides of the table in public-sector contract negotiations. Nowhere is that risk more pronounced than in California, where the perverse and pervasive effects of union political influence are on display in Cal Fire Local 2881 v. California Public Employees’ Retirement System, now before the California Supreme Court. Between 2009 and 2013, California law allowed state and local employees with over five years of service to purchase with their own funds up to five...