In most election campaigns, the challenge for the candidates is to disagree without being disagreeable.

Not so for Michael Nutter and Al Taubenberger.

In their first formal sit-down of the final stage of the mayoral campaign, the two major-party candidates were in accord on lowering taxes, encouraging economic development, improving schools, fighting crime, and several other topics.

At no point in the hour-long session, held last night at the Central Library of the Free Library of Philadelphia, did either man, on hearing the other's response to a question, seek to highlight any sort of difference.

One area of disagreement did emerge: how to deal with the planned move to full-value reassessment of residential properties in the city.

Democrat Nutter said that he supported the shift, if it could be done in a revenue-neutral fashion and with safeguards to limit annual tax increases for homeowners, particularly seniors and people with low incomes.

But Republican Taubenberger opposed it, saying that the assessment of a home should be based on what the buyer paid for it - regardless of when it was purchased - rather than current value.

More typical of the evening, though, were the moments of vehement concurrence.

For instance, in talking about crime, Nutter stressed a proposal he made during the primary: that the city provide businesses with tax incentives to hire released prisoners. The idea is to make ex-convicts less likely to return to crime.

"If you do the crime, you do the time," Nutter said. "But the time can't last forever."

Taubenberger said that he couldn't agree more.

"Before I became a candidate, I'd have given you a hundred reasons why businesses shouldn't hire an ex-convict," he said. "Today, I'd give you a hundred reasons why they must."

In a night that was heavy on smiles and chummy kidding, the lightest moment came when a questioner in the crowd of about 250 asked the candidates how they would be ground-breakers as mayor.

Taubenberger, the president of the Greater Northeast Philadelphia Chamber of Commerce, made note of his age, 54, and his hair color, gray, before answering.

"In all of my life, I've never seen a Republican mayor in Philadelphia," he said. "And going back to the days of King George, there's never been a mayor from Northeast Philadelphia. I'll be breaking ground."

The crowd laughed along with Taubenberger. The last time the city elected a Republican mayor was 1947. With Democrats outnumbering Republicans in the city by a 5-1 ratio, it's not considered likely to happen on Nov. 6.

"How do you follow a guy talking about King George?" Nutter asked before getting serious and speaking about his efforts as a City Council member to help push through a citywide ban on indoor smoking.

"You can expect the same kind of dynamic leadership if I'm mayor of this city," he said. "We've got a lot of work to do."

The joint appearance was part of the library's "Talk About It!" series and was moderated by William Sasso, the board chairman of the library's foundation.