Conservative leadership contestants turned on Kevin O'Leary in a testy debate on the West Island of Montreal, questioning his conservatism and claiming the businessman and television personality has no plan to back up his rhetoric.

But O'Leary, participating in his second debate after attending one in Halifax earlier this month, did not strike back at his rivals, focusing instead on Prime Minister Justin Trudeau and the need to grow the Conservative Party base.

In this bilingual debate (though largely conducted in English), the struggles some candidates have had in French continued. O'Leary, speaking the language for the first time on a debate stage, read out his entire opening statement in stilted French, while Lisa Raitt sprinkled hers with a few French phrases and Kellie Leitch stumbled when she forgot a word.

Steven Blaney, meanwhile, held up a glass of milk during his opening statement — a nod to his opposition to Maxime Bernier's plan to end supply management — and told the room of West Islanders that they were (in English) "pure wool Quebecers."

Blaney and Bernier later sparred over agricultural supply management in some of the more heated moments of the night.

The debate, organized by the Lac-Saint-Louis and Pierrefonds-Dollards Conservative riding associations, was held in Pointe-Claire, Que., with 11 of the 14 contestants attending. Pierre Lemieux, Deepak Obhrai and Brad Trost did not participate. Lemieux and Trost, who registered too late to participate, did attend and spoke briefly when Rick Peterson and Kellie Leitch surrendered one of their chances for a rebuttal.

O'Leary, Bernier targets of attacks

O'Leary was the target of early attacks in the debate, with Erin O'Toole questioning whether O'Leary was a Conservative, Andrew Scheer saying that "most" of the candidates on the stage were Conservative, and Andrew Saxton joking he was a good candidate to be leader because at least he "lives in Canada."

Bernier, though he was another frequent target, received less attention from other candidates than he did in previous debates.

This echoed a Mainstreet Research poll of Conservative Party members published Monday by iPolitics, which suggested that O'Leary is the front-runner, followed by Bernier.

Bernier was also the fundraising leader of the race in 2016, before O'Leary threw his hat into the ring.

Kevin O'Leary, a liberal?

When a question from the audience challenged the conservatism of O'Leary, as well as that of Michael Chong and Chris Alexander, the latter two denied they were liberals. Chong said his platform was based on conservative principles, free markets and small government, while Alexander pointed out that he had been the immigration minister who supported the removal of the veil during citizenship ceremonies and the revocation of citizenship from dual citizens convicted of terrorism.

O'Leary, however, said that the Conservative Party needed to grow. "LBGTQI: done; marijuana: done; reproductive rights: 100 per cent. Get used to it. That is the definition of the Conservative Party going forward."

O'Toole took issue with this, saying that it was up to the members of the party to decide who belonged to the party, not O'Leary, while Scheer said it was not the job of the leader to impose his views on members and that "we need to be more than liberals who are good at math."

Candidates debate immigration

Questioned on what the Conservative Party needs to do to renew its engagement with minorities, Leitch reiterated her plan to screen immigrants to Canada for "Canadian values," after denouncing the recent attacks in a Quebec City mosque. She also attacked her rivals for "having their heads in the sand" over the issue.

O'Leary advocated teaching children about other cultures at a young age, as "you cannot legislate or create a bill to eradicate intolerance and hatred. Impossible. You can only do that through education."

Chong emphasized the party's need to win back ethno-cultural communities, otherwise "we'll hand the next 15 years to the Liberal Party of Canada."

Candidates also sparred over fiscal policies and steps needed to slay the deficit, though there was little new ground broken on these issues, this being the seventh official or unofficial debate to have taken place so far.

'Trump does not respect rhetoric'

The challenges posed by the new Trump administration were also tackled by the candidates, Bernier suggesting that lower corporate and capital gains taxes would help make Canada a more attractive place in which to invest.

"We don't need to be competitive," said Bernier. "We need to be better."

O'Leary criticized the Liberal government for not pivoting after the election of Donald Trump last fall, leaving the country "the most uncompetitive jurisdiction in North America," but Peterson — the only other non-politician in the race — reminded O'Leary that the question was "what's the plan, not what's the problem."

Peterson proposes that the corporate tax rate be brought to zero.

"Donald Trump does not respect rhetoric," said Peterson as he gestured to O'Leary. "Donald Trump does not respect half measures."

O'Leary's French: 'I'm working on it'

Peterson, Bernier and Scheer all avoided delving too deeply into the linguistic tensions in the West Island when asked a question on the issue, saying that language was the jurisdiction of the provincial government. But Scheer said that anglophone rights in Quebec, as well as francophone rights outside of Quebec, matter.

O'Leary said that "you can't lead this country without respecting its past." And in response to people who criticize him for not speaking French, he said, "I'm working on it." He promised he would debate Prime Minister Justin Trudeau in French in the 2019 election.

The debate was moderated by Beryl Wajsman, editor in chief of the Suburban Newspaper Group. The next official debate organized by the party will be held on Feb. 28 in Edmonton. The leader will be chosen on May 27.