With the marching band from Girard Academic Music Program (GAMP) performing the theme from Rocky, a coalition of educators, parents, and community, government, and business leaders Thursday launched a campaign to challenge efforts to slash Philadelphia School District funding.

At a briefing at the district's headquarters at 440 N. Broad St., representatives from "Our Students, Our Philly, Our Future" previewed two public-service announcement videos that are being sent to TV stations. They also announced plans to send busloads of district supporters to Harrisburg on Tuesday to address legislators and officials who are faced with plugging a deficit of between $4 billion and $5 billion in the state's $28 billion general fund.

The coalition has come together "to stand up and stand ready to protect and preserve public education in Philadelphia," said Sandra Dungee Glenn, former chairwoman of the Philadelphia School Reform Commission, who presided over the event and introduced several speakers.

"There is too much at stake for us to sit idly by and risk losing the progress that has been made," said Dungee Glenn, who now serves on the state Board of Education.

The district is facing a $40 million shortfall in the current $3.2 billion budget that ends June 30, and a looming gap in the next fiscal year of between $400 million and $500 million.

Although Gov. Corbett has not yet released his budget proposal, his plan might include reducing state support for education. And a state Senate bill authorizing vouchers and increasing scholarships for students to attend nonpublic schools could also cut into the amount of state funds for public schools.

While the fiscal constraints are real, Dungee Glenn said, major reductions to the district budget would threaten the progress has made over the last eight years, including rising test scores, improved high school graduation rates, and a decrease in violent incidents reported by city schools.

She noted that when she joined the School Reform Commission in 2002, less than 20 percent of students were performing at grade level in reading and math. Now, more than 50 percent are at grade level.

"There is one fundamental investment we can't go back on," she said, "and that's public education."

Deputy Superintendent Leroy Nunery warned that if massive cuts are implemented, the district will be forced to end summer school, increase class sizes, and reduce or eliminate extracurricular programs, including arts and sports.

GAMP is a magnet school in South Philadelphia, and 100 percent of its seniors have been accepted into college, officials said. On Thursday, the school's choir performed two numbers, including a song from its recent production of the musical Hairspray.

"This epitomizes what we are here for. GAMP is a school that is dedicated to the arts and music," Dungee Glenn said. "But the students wouldn't get to GAMP if we didn't seed our elementary schools with art and music programs so they can identify their talents."

Afterward, Dungee Glenn said the coalition already had begun one-on-one briefings with local legislators. She said members plan to educate the public and the leadership in Harrisburg about the strides that have been made by city schools and Superintendent Arlene C. Ackerman's strategic plans for continuing the reforms.

"I don't think many people know what progress has been made," she said.