Ridge spokesman Tim Reeves said the governor, who opposes most forms of gun control, would sign Senate Bill 167 into law by the end of the week.
Ridge, a potential Republican vice presidential candidate, has said he believes that the right to sue rests with victims of gun violence or with states rather than with cities.
Rendell nonetheless urged Ridge to consider the broader implications of the issue.
"Many legislators say that gun violence is just a Philadelphia problem," Rendell said. "If that is true, why not let Philadelphia have the power to bring suit, to take care of its own problems?"
Rendell's last-minute effort could steal the thunder from Mayor-elect John F. Street, who has promised to sue gun manufacturers. On the campaign trail, Street cited statistics showing that 273 of the city's 340 homicides last year were committed with guns - and that gunshot wounds are the leading cause of death among Philadelphia residents 16 to 21.
Street was not present at Rendell's City Hall news conference yesterday. Late yesterday afternoon, Street offered a short, formal response.
"Ed Rendell has long espoused the option of filing a municipal lawsuit against gun manufacturers. He is still mayor of this city until year end and is therefore authorized to send today's letter to the governor," Street said, through his spokesman, A. Bruce Crawley.
"For my part, I also oppose the bill's passage, but I will reserve the right to bring a lawsuit on behalf of the citizens of Philadelphia whether Bill 167 is passed or not."
Rendell has spent much of his second term looking for ways to lessen the impact of gun violence on Philadelphia. He was the first big-city mayor to seriously talk about and research the notion of holding gun manufacturers liable for the soaring costs cities incur because of gun violence - including treating uninsured victims, paying police officers overtime and cleaning blood off city streets.
Instead of suing, Rendell has tried to negotiate with gun makers. While he waited, Boston, Chicago, Camden and 25 other cities have moved to sue, using a strategy much like state attorneys general did against the tobacco industry.
Reeves said Ridge and the legislature see gun use - and misuse - as a statewide issue. Largely rural, Pennsylvania is home to one million hunters, and some studies show guns in more than 50 percent of the state's homes.
In 1994, the state passed a law nullifying a Philadelphia ordinance that banned assault weapons on the ground that the state, not municipalities, should regulate who can own what type of guns.
"This is not uncharted territory," Reeves said. "The Pennsylvania General Assembly has historically determined that issues affecting basic constitutional rights should be decided on a statewide basis, rather than having 5,000 different municipal interpretations."
Rendell also invoked the now-famous tobacco lawsuits that yielded hundreds of millions of dollars in settlements for states.
"Had Congress passed, and the President signed into law, legislation barring states and local governments from suing the tobacco manufacturers, we wouldn't have the settlements we've had across the nation," Rendell said.
Reeves said it was state attorneys general, not cities, that sued tobacco companies. Under the pending legislation, Pennsylvania would retain its right to sue gun makers. So would individuals.
Further, Reeves said, there is the matter of the constitutional right to bear arms: "There's not an amendment to the Constitution allowing the right to light up a cigarette."