Before their biggest television audience yet, Allyson Y. Schwartz and Rob McCord pounded front-runner Tom Wolf on Monday night as unprepared to be governor, and accused him of ducking tough questions about his past, during the final debate of the Democratic primary campaign.

There were no policy thunderbolts in the hour-long debate at Drexel University, with all four candidates in broad agreement that school funding must be increased, natural gas drilling taxed, and ethics rules in Harrisburg tightened.

It was the second debate of the day with a striking number of references to race and racism.

McCord kept up his attack against Wolf for not swiftly disavowing then-York Mayor Charlie Robertson, an admitted former racist, when he was the mayor's 2001 campaign chairman. After winning the primary, Robertson was charged, and later acquitted, in the shooting death of a black woman during the city's 1969 race riots, when he was a police officer.

"The real issue was your failure to speak up, to confront racism publicly," McCord said. He twice contrasted what he called Wolf's slow response with the NBA's quick decision to ban the owner of the Los Angeles Clippers for recent racist statements.

"I stayed in the campaign for the two or three days it took to get him out of the race - that was the sum total of my connection with Charlie Robertson," Wolf retorted. "I was actually responsible for getting him out of the race."

Schwartz said Wolf had been "not been able to face the cameras to answer these questions," and said his background as owner of his family's building-supplies business, a Peace Corps volunteer, and state revenue secretary was no match for her own 23 years in the Pennsylvania Senate and U.S. House working on major legislation.

"Being CEO of one family company is not the training we've been sold in those fuzzy ads," McCord said. He also said Wolf, who has put $10 million of his own money into the campaign, had turned the contest into an "auction and not an election."

Katie McGinty, the former state environmental secretary, said her rivals were raising "serious issues" that she expected Wolf would be able to explain to the voters.

"But what I hear the voters talking about is the fact that their son or daughter no longer has tutoring after school, that they now have to pay 150 bucks if they want their son or daughter to be able to participate in sports, the fact that we're now dead last in the region . . . in private-sector job creation," McGinty said.

At one point, a woman stormed the stage, yelling that the candidates had "failed the test of leadership" by not supporting a ban on fracking natural gas from shale. Moderator Larry Kane asked security guards to "take her out," but the forum was disrupted for several minutes until she could be hustled away.

The debate, the last of more than a dozen, was carried live on 12 TV stations and nine radio stations statewide. It was also broadcast on PCN and streamed live on Drexel's website.

McCord also criticized Wolf's 2001 decisions at a forum earlier Monday, sponsored by WURD-AM radio and aimed at issues concerning African American voters.

At the end of the evening debate, which was sponsored by Drexel and the Democratic City Committee, moderator Kane forwarded a question from that committee's chairman, U.S. Rep. Robert Brady: After next Tuesday's primary, would all four attend a unity breakfast at the Union League?

All said yes, though McCord quipped that the historically Republican club might not be the best locale.