For years, the School District of Philadelphia, the city's charter schools, and the Archdiocese have been more likely to compete than to cooperate. But with money for schools increasingly scarce, the long-time adversaries have joined forces to seek outside help.

For months, Lori Shorr has been telling anyone who will listen that Philadelphia's district, charter, and Catholic schools need to start working together.

"We have different types of schools in this city," Shorr said. "We can either aggressively move to have them work together, or we can pretend it doesn't exist and hope everything turns out all right in the end."

Shorr is Mayor Michael Nutter's chief education officer. She's also the driving force behind Philadelphia's Great Schools Compact, a new partnership that just asked for two-point-five million dollars from the Bill and Melinda Gates Foundation. Most of the money would be used to help develop better teachers and principals for schools in all three of the city's education systems.

"We are focusing on things that all schools need," said Mastery Charter Schools CEO Scott Gordon. "If the grant comes through, Mastery would begin training other schools' teachers — and send some of its future principals through a yearlong residency program run by someone else."

"This really is a new day," continued Gordon. "The walls that separated District from charters from Archdiocese and so forth are disappearing. They're not gone entirely, but I think what binds us together is much greater than what separates us."

The Philadelphia Great Schools Compact is expecting to hear back from the Gates Foundation early this fall. In the meantime, the group is pursuing a number of other initiatives, including a common application and enrollment system that would cover every District and charter school in the city.