"Because we have a one-party system in Philadelphia, there is not always a force to push back against the powers-that-be on behalf of working families," said Bishop Dwayne Royster, executive director of the faith-based community group POWER ( Philadelphians Organized to Witness, Empower and Rebuild) and pastor of Living Waters United Church of Christ in the Oxford Circle section.
Nationally, Working Families has won recent victories on social-justice measures in New York, Connecticut, and Oregon. Its strategists believe the group is riding an updraft in U.S. politics, with concern over rising income inequality and a sense on the left that leading Democrats are in thrall to Wall Street and corporate interests.
The group also is active in New Jersey, organizing demonstrations against Gov. Christie over "Bridgegate" and wading into the recent Newark mayoral race - by linking one of the contenders to Christie, the state overseer of the city's schools, and Wall Street.
In Philadelphia, Working Families surfaced last November, hosting a forum for Democrats running for governor at Temple University and drawing a raucous crowd of hundreds of union members and community activists.
If the coalition is new, its member organizations are not. The Pennsylvania Working Families includes such liberal and labor mainstays as MoveOn.org; District 1199c of the national health workers union; the Pennsylvania Association of Staff Nurses and Allied Professionals; Local 32BJ of the Service Employees International Union (SEIU), which represents property maintenance workers; and AFSCME District Council 47.
Its troops knocked on 40,000 doors in the weeks leading up to the May 20 primary, identifying 16,100 "yes" votes for Question 1, said Kati Sipp, the executive director of Pennsylvania Working Families.
That question was about wages. The city's living-wage law requires municipal contractors to pay workers at least 150 percent of the federal minimum wage - or $10.88 currently. The ballot question proposed extending that to subcontractors, who employ thousands of workers at Philadelphia International Airport.
Aiming at the fall ballot, the group collected 39,225 signatures - 20,000 are required - to get a nonbinding referendum on returning local control to the city's schools. City Council must certify the signatures and pass a bill setting the question.
"We're attacking some issues that people want to see attacked, with a different voice and new ideas," said Chris Woods, executive vice president of 1199c, who has been involved in organizing the coalition.
"I think it could be a new movement," Woods said. "It gives an option and some hope to folks who think important things aren't getting done."
He said the group would be considering "what kind of player we want to be" in the 2015 municipal elections, when the city will elect a new mayor.
David Dunphy, a Philadelphia-based Democratic strategist, said the rise of the Working Families group here was driven by the "intellectual argument for the hearts and minds of the Democratic Party between progressives and corporate Democrats."
Real power will come at the ballot box, he said. "Where it matters is where you can impact an election," Dunphy said.
One possible tool, he said: Philadelphia's City Charter reserves seats on Council and at least one of the city commissioner slots for members of the minority party in the city. But nothing says that has to be the GOP.
The Working Families Party has a permanent line on the ballot in New York, and it was part of the coalition that elected liberal Democrat Bill de Blasio last year. A majority of the City Council there also had Working Families backing. Unlike Pennsylvania, New York allows "fusion" voting - meaning that a candidate for office can run with the nomination of more than one party.
And in Oregon, Working Families was instrumental in enacting Pay It Forward, a program that allows in-state students to attend public colleges or universities tuition-free, with graduates paying a portion of their incomes into a fund to finance the educations of future students.
In Bridgeport, Conn., a slate of candidates backed by that state's Working Families Party took control of the school board last year, put a brake on charter schools, and booted out Superintendent Paul Vallas, who once headed the Philadelphia School District.
"The purpose of the Working Families Party is not to become a machine, just a vehicle to elect candidates you like, but to develop a progressive agenda and build support for it in the electorate," said Gabe Morgan of Pittsburgh, state director of SEIU 32BJ, one of the steering committee for the new group.
"The point," Morgan said, "is to drive an agenda."