The Los Angeles County Board of Supervisors voted 3-2 along ideological lines Tuesday to urge voters to vote no on Proposition 32 on the Nov. 6 ballot.
The measure would prohibit unions, corporations, government contractors and state and local government employers from spending money deducted from an employee's paycheck for political purposes.
Supervisor Mark Ridley-Thomas, who recommended the action, said the proposition would limit the voice of hardworking Californians.
"Proposition 32 is restrictive legislation that advantages billionaire campaign contributors and super PACs by prohibiting working Americans from collectively contributing money to their own political action committee through their unions," Ridley-Thomas said. "Corporations already outspend unions by more than 15 to 1 in politics."
Supervisors Don Knabe and Michael Antonovich were the dissenting votes.
Knabe said he understood others' concerns that prohibiting payroll deductions would lead to a drop in political fundraising by unions, but said he saw other valuable reforms in the ballot measure.
"At some point we have to deal with campaign reform," Knabe said.
Dozens of union members and other activists rallied before the board's vote and several spoke out on Proposition 32 and Proposition 30, also set for the November ballot.
Before the vote to oppose Proposition 32, the board voted on the same 3- 2 split to support Proposition 30, the sales and income tax increase backed by Gov. Jerry Brown to increase education funding.