SAN FRANCISCO (KPIX 5) — Whether it’s a protest against tech company shuttles known as “Google Buses,” high rents, or Twitter’s tax breaks, San Francisco has become ground zero in the new war between the haves and have not’s.

As it turns out, many of the fights are actually being stoked by the politically powerful Service Employees International Union, which represents thousands of San Francisco city workers. Coincidentally they are also in the midst of negotiations with the city for a new proposed contract.

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What is the union’s pitch? “We want a program that makes the city a place not just for the wealthy can thrive, but where low, moderate, middle income people can also thrive,” said Larry Bradshaw of the SEIU.

That contract would include a 15 percent pay raise over the next three years. The city would pay 85 to 100 percent of medical coverage, and a $21 an hour minimum wage for full and part time city workers.

City officials said it’s a package that they can’t afford.

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“If you say you can’t afford it, then why are we giving tax breaks to corporations like Twitter that are valued at $36 billion a year?” Bradshaw said.

Christine Falvey of Mayor Ed Lee’s office told KPIX 5, “City workers by average make more than their counterparts in other Bay Area cities and sometimes even the private sector – we do that because we know that San Francisco is an expensive place to live.”

“When you treat Google, when you treat Twitter, and treat Zynga and these other very profitable corporations different, people start to get resentful of that,” Bradshaw said.

“SEIU is going to talk about inequality, the Mayor is going to talk about the need to balance the budget, both of them are right,” political consultant Eric Jaye told KPIX 5. “It’s going to be Google buses. It’s going to be the Twitter tax break. It’s going to be whatever draws your camera to create the noise that they think they need to get a good contract.”

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Contract negotiations are continuing and it appears that it could be going to arbitration. The union could also be hitting the streets over a ballot measure to raise the minimum wage in San Francisco.