By way of comparison, the Knox campaign spent just under $348,000 on ads last week, compared to about the same amount by U.S. Rep. Bob Brady, roughly $300,000 by former City Councilman Michael Nutter, $225,000 by U.S. Rep. Chaka Fattah and $193,000 by state Rep. Dwight Evans.
"We have to combat these illegal 527s smearing Tom's name all over town," explained Josh Morrow, Knox's campaign manager, referring to ads aired this past weekend by political committees formed under Section 527 of the tax code.
Such committees are, in fact, illegal only if they fail to maintain independence from the candidates themselves. The city Board of Ethics is looking into any links between the candidates and two 527s formed with the apparent intention of damaging Knox. The candidates have denied any involvement.
The ethics board is moving quickly, its interim head said yesterday. J. Shane Creamer Jr. declined to say if subpoenas had been issued, but noted that "there is very little time between now and the election to take action that may be appropriate."
During the debate, which was hosted and broadcast by KYW Newsradio, Knox said he would cap his spending at the amount he has contributed to the campaign thus far. He refused to specify how much that was - it's believed to be about $7 million - saying the amount would be revealed in the campaign finance filing due Friday.
But later in the day, Morrow said that such a self-imposed limit might not last long: "If these guys keep attacking us, we're not going to cap our spending."
In a statement issued late in the day, Brady said: "We all knew that Tom Knox wanted to buy City Hall, but now it looks like he might make a run at buying the entire Avenue of the Arts, too."
A new Knox commercial mentions the attacks as one more reason why Philadelphia needs the change he is offering. An independent survey last week put Knox, the leader in the polls for weeks, in a statistical tie with Nutter.
In the debate, Knox still seemed to be wearing the front-runner's bull's-eye on his back.
Brady accused him of having profited in business by "ripping off" working men and women. Evans asked, "Where's the beef?" in Knox's record. And Fattah wondered who would be hurt by the cuts Knox might make in city services.
For his part, Knox questioned the value of the decades of experience in city, state and federal office represented by Brady, Evans, Fattah and Nutter. "So let's see: Has crime gone down?" Knox asked. "Have jobs gotten better? Has pay gone up? Has our salary level gotten better? Is our educational system better? Is homelessness down? If it's not down, then I'm going to take my 40 years of business experience and put it against their results."
Knox also was called on to explain some of the practices of businesses he has owned, including Crusader Bank, which in 1999 and 2000 made payday loans - money borrowed in anticipation of a paycheck - charging $17 per $100 for money paid back in two weeks. Federal regulators admonished the bank to give up these practices.
"We had less than two percent of our assets invested in predatory lending or payday loans," Knox said in the debate. "When we were told it wasn't a good business to be in, we got out of it."
The two candidates running closest to Knox in the polls, Nutter and Fattah, came in for gentler criticism during the debate.
Nutter took some heat over his proposal to allow police in high-crime areas to stop, question and frisk people suspected of carrying illegal weapons.
In explaining his plan, Nutter cited a U.S. Supreme Court decision and mentioned that 73 percent of the city's murder victims in 2006 were black men.
Evans was not impressed, saying "I don't think we should break the law to make the law."
Commented Fattah: "I really don't care what the ethnic makeup of the victims is."
Brady, Nutter and Knox had harsh words for Fattah's proposal that Philadelphia ought to study imposing a congestion charge on suburban commuters driving into Center City.
Such a charge would reduce pollution and provide a funding source for SEPTA, said Fattah, noting that New York City is studying the idea for Manhattan.
Nutter said such a charge would be "devastating" for retail businesses and city-suburban relations. Brady quipped that "the only one thing worse than traffic is no traffic." Knox claimed a congestion charge wasn't feasible, noting that Center City, unlike Manhattan, isn't an island.
Even with all of the critical words, there were times when candidates came to each other's defense.
At one point, Nutter was asked why he, a Democrat, had agreed to accept Republican support to become chairman of the Convention Center Authority in 2003. After Nutter answered, Brady backed him up with words of praise for Nutter's work at the center.
A smiling Brady then turned to Nutter and silently mouthed the words, "You owe me one."
Later, each candidate was asked which of the other four he'd support were his own name not on the May 15 ballot. Only Knox answered directly, saying he'd vote for Evans.
After the debate, Evans put out a news release accepting Knox's "endorsement." Said Evans: "Maybe I should have asked for a campaign contribution from him this morning, too!"
In other campaign developments yesterday, Fattah was endorsed by a "Clergy Coalition" of several dozen pastors with tens of thousands of congregants of various faiths - this on the heels of a Sunday night rally at which a larger group, Black Clergy of Philadelphia and Vicinity, proclaimed its support for Evans.
Several of the ministers at Fattah's event praised the congressman's record and promised to use their influence to help get him elected. "He is willing to dig into frustrations that breed unrest and violence," said Rev. Dr. Jacob L. Chapman of Pinn Memorial Baptist Church in Wynnefield.
In accepting the endorsement, Fattah said: "It may be difficult for people outside of the clergy to understand the power that's in this room, but I understand it."
Contact senior writer Larry Eichel at 215-854-2415 or email@example.com.
Inquirer staff writers Marcia Gelbart and Andrew Maykuth contributed to this article.
To read our profiles of the candidates, along with their campaign promises, our reporters' blog and more, go to http://go.philly.com/mayor