California labor unions have formed a coalition to fight Proposition 32, a campaign finance measure that will appear on the November ballot. The main purpose of the measure is to prevent both corporations and unions for making direct contributions to candidates, but another element -- the prohibition of political contributions through payroll deduction -- would unfairly impact unions, according to the labor coalition. So far, the unions have raised nearly $10 million, far more than the Proposition's supporters.
See "Unions raise nearly $10 million to fight Prop. 32", Michael J. Mishak, Los Angeles Times, July 31, 2012