Patrick Brown's departure from the Progressive Conservative leadership race was chaotic for the party, but it may have buoyed the campaigns of Doug Ford and Christine Elliott, as many of the former leader's supporters have bolted for one of the two camps in the past week.

Ontario's Tories began voting on Friday in a leadership contest that supporters of the three main campaigns have said will be tight. However, in the days since Mr. Brown abandoned his run to reclaim his old job, legislators and supporters who had stood by the 39-year-old leader have largely avoided Caroline Mulroney, a political newcomer who took a hard line against the former leader. The eventual winner, according to several party members, will be the candidate who can persuade voters that they would do the best job of uniting a party that has suffered a difficult month of infighting and can lead them to victory against Premier Kathleen Wynne's Liberals during the June election.

Read More: How Patrick Brown's private life became a problem for the Ontario PCs

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The four candidates are Mr. Ford, a former Toronto councillor, Ms. Mulroney, who has raised more money than all the other candidates combined, Ms. Elliott, a former MPP, and Tanya Granic Allen, an activist who opposes Ontario's new sex-education curriculum. Former MP Paul Calandra had supported Ms. Mulroney, but switched to Ms. Elliott in late February. The PC candidate in Markham-Stouffville, Mr. Calandra said he expects the race to be a duel between Mr. Ford and Ms. Elliott.

"I heard from a lot of people who wanted us as a party to get our acts together, and I realized the right person to bring us together, with deeper roots in the party, was Christine Elliott," he said. Ms. Elliott lost two previous bids for the leadership.

He said Ms. Mulroney is a strong candidate, but feared "her team hasn't been up to the job."

The six-week campaign for the leadership, the shortest in the party's history and the closest to a general election, was dominated by Mr. Brown – his resignation, his choice to run for his old job, and his eventual withdrawal on Feb. 26. Mr. Brown's withdrawal changed the race, said Rod Phillips, the party's star candidate in Ajax and the former head of Ontario Lottery and Gaming Corp. One of Ms. Mulroney's strongest supporters, Mr. Philips said crowds at her events have been growing beyond expectation since then.

"What I judge this by is momentum," he said. "I just introduced her and we had 100 people more than we expected. The crowds are telling me that there is enthusiasm for her new approach."

According to Elections Ontario, Ms. Mulroney's camp has raised more than $703,000. By comparison Mr. Ford has disclosed $63,424, and Ms. Elliott $122,030. The money is a sign that people like Ms. Mulroney's message, Mr. Philips said.

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One of the senior conservatives who has endorsed Mr. Ford since Mr. Brown withdrew is MPP Toby Barrett, who was caucus chair for the former leader. He said many of Mr. Brown's supporters do not want to vote for anyone who may have helped undermine the former leader when he was trying to save his career.

Ms. Mulroney had called on Mr. Brown to step down, Ms. Granic Allen called the former leader "corrupt," while MPP Randy Hillier, who supports Ms. Elliott, filed a complaint with the province's integrity commissioner about Mr. Brown's personal finances.

"I don't think Patrick Brown's loyalists would be amenable to joining those teams," Mr. Barratt said, so he backed Mr. Ford, whose embrace of business he supports. "He also brings a tremendous amount of political experience in one of the hottest political arenas anywhere, the City of Toronto. It makes Queen's Park look staid and predictable."