OTTAWA -- The Ontario Progressive Conservatives' efforts to leave behind weeks of unprecedented chaos took a hit Wednesday as the controversies splintering their ranks came into the spotlight at the last debate of the party's leadership race.

The four candidates vying to seize the reins of Ontario's Opposition each painted themselves as the only one equipped to clean up the mess left by former leader Patrick Brown as well as take on Liberal Premier Kathleen Wynne in the province's spring election.

Brown's abrupt resignation amid allegations of sexual misconduct in January fuelled tensions within the Tories and brought scrutiny upon the party's structure, vetting practices and nomination process, which led party brass to overturn nominations in two ridings and declare there were fewer party members than initially believed.

Those issues re-emerged in Wednesday's debate, with all four candidates -- former Tory legislator Christine Elliott, Toronto lawyer and businesswoman Caroline Mulroney, former Toronto city councillor Doug Ford and social conservative advocate Tanya Granic Allen -- vowing to tighten and enforce rules regarding sexual harassment and party nominations.

Granic Allen in particular repeatedly asked her competitors if they would reopen nomination contests where there had been allegations of interference, candidate bullying and corruption.

"We have to address the corruption in our party," she said. "The three of you have stood idly by as the party was run into the ground by Patrick Brown and his corruptive practices."

Ford said he would reopen problematic races and recounted a story of being at nominations where he had heard accounts of ballot stuffing.

"When I'm leader I'm going to make sure they're transparent, people are held accountable and there's going to be integrity here," he said.

Elliott said she would ensure party rules were followed for races to be conducted properly, while Mulroney said she had a plan to ensure party processes were as fair as possible

"We need to make sure our nomination process is as fair and open and transparent as possible," Mulroney said. "We need to make sure we're as strong as we can be."

Brown, who has repeatedly denied the allegations against him, was himself a topic of debate as those competing to succeed him were asked whether they would allow the Barrie, Ont., politician to run under their banner.

Elliott and Mulroney said they would let Brown back into the fold if he cleared his name of the sexual misconduct and financial impropriety allegations against him before the campaign.

Though Brown has declared that his name has already been cleared, both Elliott and Mulroney said it would be up to others to make that call.

"Saying you've cleared your name and clearing your name are two different things," Mulroney said.

Ford said only that Brown "has to take care of a few things," and said he was focusing his attention on Wynne instead.

Granic Allen has so far been the only one to say unequivocally that Brown would not be welcome in the party under her leadership, though she stressed her opposition stems from his management practices rather than the sexual misconduct allegations.

Brown -- who launched a bid to reclaim his old job a day after the first leadership debate earlier this month -- was expected to join the four candidates for the Ottawa event being hosted by Althia Raj of HuffPost Canada.

But he backed out of the race Monday, saying his candidacy had caused hardship for his friends and family, and had drawn focus away from the party's goal of defeating the governing Liberals in the spring election.

His departure in late January set off what the party's interim leader, Vic Fedeli, has called a period of "unprecedented" tumult.

With Brown out of the leadership race, Fedeli -- who weeks earlier vowed to clear the "rot" from the party -- said the Tories are ready to close the door on what has been a difficult chapter in their history.

He said the party has emerged from its ordeal stronger and with more momentum than before, citing a boost in membership numbers and fundraising. Some experts, however, have said it may not be that easy for the Tories to turn the page.

Voting for the new leader is set to begin online on Friday, although Tory members have until 11:59 p.m. on March 5 to sign up to cast their ballots. The party's leadership election committee said Brown's name has been removed from the ballot.

The winner will be announced on March 10.