San Antonio's politically powerful firefighters' union will fight against a November ballot measure that would eliminate the city-manager tenure and pay limits that the labor organization successfully sought to implement in 2018. The San Antonio Professional Firefighters Association voiced its opposition to Proposition C in a Monday news release. The move sets up an influence battle with RenewSA, a business-backed political action committee that supports the proposition and five other changes to the city code voters will decide on this fall.