OTTAWA -- Kevin O'Leary is dropping out of the Conservative leadership race, citing weak second-ballot support and a lack of popularity in Quebec.

Even as he explained the reasons for departure, the Canadian politics outsider, who built a business and celebrity profile in the U.S., peppered his explanations with references to American politics and his prominence in the country south of the 49th parallel.

O'Leary says his outsider status limited his second-ballot support, and cited his weakness in Quebec as the reason he was quitting.

"The real reason is I only got the 12% in Quebec. That's a fact," he told reporters at a press conference Wednesday afternoon, comparing Quebec to Florida, a state that can determine a U.S. election.

"The Conservative Party needs someone who has the best chance of beating [Prime Minister Justin Trudeau]. Someone who will command the support of Canadians from every region of the country and who can build a consensus among all members of the party," O'Leary said in an email to supporters.

"Second ballot support is always a concern for any candidate and all you can do is live with that risk and see where the votes settle."

He also said he and Bernier are statistically tied as front-runners, separately noting his strong support in the West. O'Leary said he polled as high as 34 per cent in some provinces.

All the leadership contestants are in Toronto for the last official debate of the contest, with the new leader to be announced May 27.

O'Leary and Bernier have consistently polled ahead of the other 12 competitors in the race, making this move potentially game-changing if O'Leary's supporters move their votes to Bernier.

But that's not guaranteed. The party's nearly 260,000 members aren't bound to follow their preferred candidate's direction if he or she drops off the ballot.

The winner has to take 50 per cent plus one point of the 33,800 points allocated equally among the country's 338 ridings. Each electoral district is allocated 100 points regardless of how many members belong to the riding association.

That makes it hard to predict the outcome, as does the party's ranked ballot, which will see the bottom finishers dropped off the ballot and their support redistributed round by round.

O'Leary says his team has sold 35,335 party memberships, including "a whole new generation of young Canadians, many of whom are new to the Conservative Party."

O'Leary run lasted three months

O'Leary spent a year teasing his possible entrance into the race before finally declaring last January that he would run. He had said he was waiting for some of the candidates to drop out so that the debates would be more substantive. Instead, he landed in a 14-person race and avoided several all-candidate debates, claiming the format didn't allow for proper discussion.

He was also criticized for travelling frequently to the U.S., including doing an American TV interview on a day he skipped a debate in Toronto. Even as he departed the race, O'Leary noted he had done an American TV interview the day before.

"Yesterday in New York City I defended Canada's position in our trade relationship with that country on CNBC, with [Foreign Affairs Minister Chrystia] Freeland," he said.

"I'm a very well-known Canadian to Americans."

Pressed about his frequent travel to the U.S., O'Leary defended his sincerity in joining the race.

"You think what I just did for four months was fun? I've been to towns you don't even know how to spell the name of," O'Leary said in an interview with Don Martin, host of CTV's Power Play. "Are you kidding? That was the hardest thing I've ever done."

Despite his efforts, O'Leary won little Conservative caucus support, leading a former Stephen Harper strategist to posit he was the worst-placed candidate to maintain party unity.

One concern cited by a number of MPs was O'Leary's inability to speak French. The celebrity businessman initially said it wouldn't matter because voters cared more about the economy, but eventually relented and hired a French teacher. His progress was slow, however, and he struggled with the language.

'Welcome to politics'

Still, O'Leary managed to attract several federal and provincial conservative heavy-hitters to his campaign, including former Ontario PC Premier Mike Harris and former Conservative Senate leader Marjory LeBreton.

O'Leary also claimed to be a fundraising powerhouse, although he was in the race so short a time that Elections Canada hasn't yet confirmed his first quarterly filing. He can continue to fundraise to pay off any campaign costs, and says he will fundraise with Bernier.

Even those who opposed O'Leary admitted he drew additional media attention to the race -- though not always positive attention, at least for the other candidates. Last month, he issued a press release complaining a rival was vote-rigging by signing up fake members using pre-paid credit cards. While his spokespeople wouldn't say who they suspected of the vote-rigging, other O'Leary officials privately pointed to reaction from the Bernier campaign that suggested the Quebec MP was the target of the complaint.

The party investigated and cancelled 1,351 memberships. Bernier told CTV's Question Period that the fake memberships didn't come from his campaign.

Asked about their former rivalry, O'Leary was sarcastic.

"Oh, he was critical during a campaign. Welcome to politics," he said.

Bernier said he likes competition, particularly in a free market.

"He was my biggest opponent and a strong competitor," Bernier said. "We had a nice competition and now we are together."