Two former mayors staged a bipartisan lovefest at Irvine Auditorium July 31, but a prominent critic of one of them managed to get in a few zingers.

At a panel discussion on “The Future of the City,” Philadelphia’s Ed Rendell, now general chairman of the Democratic National Committee, and Indianapolis’ Stephen Goldsmith, now George W. Bush’s chief domestic policy advisor, both noted that cities have come to rely more on their own resources in staging their revivals.

Fred Siegel, professor of history at Cooper Union and author of “The Future Once Happened Here,” agreed. “Mayors are changing from social workers to entrepreneurs, looking to each other rather than to Washington,” he said.

But Siegel and the mayors parted company on the role of federal incentives. Rendell, in the course of praising a Republican urban tax-incentive program, said that “left to its own devices, the free market will not locate in [depressed city] neighborhoods.” Siegel called the mayor’s statements false. “Once crime came down in Harlem, capital flowed in,” Siegel said. “What was required was not government getting in, but government getting out.”

Rendell and Siegel also sparred on whether retail development would be enough to revive sagging city neighborhoods. Rendell argued that cities needed to attract industry again, while Siegel, who wrote an article critical of Rendell’s later years in the City Journal, stated that “heavy industry simply isn’t coming back” to urban America.

Philadelphia Daily News columnist Elmer Smith agreed that retail alone wouldn’t bring cities back, but added that Philadelphia’s future in particular depended on “tying into the techno-boom in a way we have not done so far.”

President Judith Rodin noted that urban universities have a special interest in their cities’ overall health and stated that Penn’s increasing engagement with its community has begun to pay dividends, a sentiment Smith echoed.

The discussion, part of a special project sponsored by the Daily News, was moderated by “News-Hour with Jim Lehrer” Senior Correspondent Ray Suarez, author of “The Old Neighborhood,” and was broadcast live on WHYY-TV.