This November, California voters must decide two policy questions of great concern to public-sector unions. One is a tax hike to stave off further cuts to state spending (there are two versions on the ballot with a chance of passing). The other is a "paycheck protection" measure that would ban the practice of unions' deducting money from member paychecks to spend on political activism. Public-sector union members stand to benefit from the tax increase, and they are campaigning heavily for one version, Proposition 30, which is being promoted by Governor Jerry Brown. Conversely, the unions stand to lose money and power if paycheck protection passes, and they are working hard to defeat it. To understand what these political battles teach us about the outsize influence of public-sector unions in California politics, this study examines how public-sector unions have fared on proposition campaigns since 1980. This analysis suggests that the vote on the tax increase is likely to be very close, and the unions will probably be able to defeat the paycheck-protection measure for a third time. Union Power in the State Legislature is appended. (Contains 4 charts, 5 tables, and 37 endnotes.)