Philadelphia City Commissioner Stephanie Singer's name will not appear on the May 19 primary election ballot, Commonwealth Court ruled Thursday.

The court rejected Singer's appeal of a Common Pleas Court ruling March 30 striking her name from the ballot.

Singer needed at least 1,000 signatures from registered Democrats on nomination petitions to be listed on the ballot. She filed 1,485 but a review during a legal challenge found that just 996 were valid. That left her four names short in her bid for a second four-year term.

Singer's appeal rested in part on her claim that Judge Joel Johnson did not allow her to submit affidavits from 16 voters who claimed their names had been wrongly stricken.

A panel of three Commonwealth Court judges called Johnson "very accommodating" because he held about 40 hours of hearings over five days, allowing Singer to call any witnesses she wanted.

Singer, the judges noted, did not submit her 16 affidavits during those five days of testimony.

Singer issued a statement Thursday saying "entrenched interests were behind this injustice because they knew they couldn't beat me fair and square on Election Day."

She said she was "no longer actively campaigning," but would continue to fight for voters' rights and transparency in the City Commissioners Office.

On Tuesday, Singer equated her legal struggle to the 1965 beatings of civil-rights marchers in Selma, Ala. In an e-mail asking supporters for donations, Singer wrote:

"The heroes of Selma in 1965 were fighting for the people of Philadelphia in 2015. Today, the weapons are not billy clubs and horses - they are the courts and the media."

Singer also decried in her e-mail a "slanted legal system" in her case.

The three city commissioners oversee elections in Philadelphia.

Singer, a former Democratic ward leader and math professor, ran as a reformer in 2011. She served as chairwoman during the first year of her term but was ousted by her two colleagues one day after the 2012 general election after clashing repeatedly with them and the commission's staff.

Singer worked closely with Henry Nicholas, leader of the National Union of Hospital and Health Care Employees, to oppose the state law requiring voters to show photo identification at polling places. A Commonwealth Court ruling overturned that voter ID law last May.

Nicholas on Thursday endorsed Singer's analogy of her ballot fight and the struggle for civil rights. His union is scheduled to hold a rally Monday to support Singer.