Federal Conservative leadership candidate Michael Chong was in the rhetorical hot seat Sunday, defending his proposal for a carbon tax from skeptical rivals vying to take the party into the 2019 election.

The opposing viewpoints prompted pointed jabs during the second of two debates held in the Lower Mainland over the weekend – a gathering of about 300 people in a downtown theatre organized by the Vancouver Centre electoral district association.

Nine of the 14 candidates for the leadership attended, and the most pointed moments came when candidates took the opportunity to dismiss Mr. Chong's proposal as a bad idea for a Conservative Party seeking to return to power.

Story continues below advertisement

Campbell Clark: Michael Chong's pro-carbon-tax stance could make for a rocky Tory leadership bid

Adam Radwanski: In populist winds, the Conservatives' inclusive tent is collapsing

John Ibbitson: Voting for Conservative leader: What would Stephen Harper do?

Mr. Chong, an Ontario MP and former intergovernmental affairs minister, stood his ground, declaring the Conservatives won't gain traction with voters without a credible climate-change policy, part of which could be his revenue-neutral tax proposal.

He even cited British Columbia's ground-breaking carbon tax as an example for the federal Conservatives.

"The B.C. model works. We need to take it and export it to the rest of the country," Mr. Chong said, facing criticism, at one point, from Rick Peterson, a Vancouver-based businessman seeking the leadership.

Mr. Peterson noted that B.C. Premier Christy Clark has been wary about increasing the tax, enacted despite some opposition by her predecessor Gordon Campbell, beyond $30 a tonne.

Story continues below advertisement

Mr. Chong said the B.C. tax was three times the price on carbon of any other province, and that the Liberals have been re-elected in B.C. despite enacting the tax.

Steven Blaney, a former public-safety minister, was skeptical. "Michael, I disagree with your green tax. I believe that a tax is a tax is a tax. We've seen that movie before with [former federal Liberal leader] Stéphane Dion and his green tax," said the Quebec MP, drawing laughter from the audience.

Mr. Blaney suggested emphasing clean energy, particularly nuclear energy where hydro is not possible. "We must invest in technology to have green and clean energy, but no more taxes."

Erin O'Toole, an Ontario MP and former veterans affairs minister, also piled on, saying, in response to a question from moderator Kirk LaPointe, that the first tax he would kill as prime minister is the federal Liberal carbon tax.

"With respect, Michael, I am not in this race to out-Liberal the Liberals," he quipped, proposing a federal Tory government would work with large emitters to reduce their carbon footprints.

But Mr. Chong insisted the cheapest way to reduce emissions is a revenue-neutral carbon tax, and noted it would consist of a tax cut. Mr. Chong has proposed a levy that would reach $130 a tonne by 2030 and help finance an $18-billion tax cut.

Story continues below advertisement

On Saturday, all of the candidates, save Kevin O'Leary and Deepak Obhrai, attended a debate hosted by a nursery in Langley, east of Vancouver. Mr. O'Leary and Mr. Obhrai, as well as Maxime Bernier, Kellie Leitch, and Pierre Lemieux, did not attend Sunday's debate.

Neither of the B.C. weekend events were official party events, thus there was no obligation for leadership candidates to attend.

However, Chris Alexander, Lisa Raitt, Andrew Scheer, Andrew Saxton, Brad Trost, Mr. Blaney, Mr. O'Toole, Mr. Peterson and Mr. Chong were on stage for a debate that featured candidates facing off against each other as well as all present engaging in a larger discussion.

Topics addressed during the two gatherings included the fentanyl crisis, the wisdom of diplomatic relations with Iran, affordable housing, U.S. President Donald Trump and a section on legalizing marijuana that led Ms. Raitt to issue a stern warning to the party.

"I'm going to get real with everybody in the room. If we run an election in 2019 on the platform of recriminalizing marijuana, we will face the same result as we faced in 2015," she said, eliciting cheers and applause.

Speaking to 2019, she said the focus should be on the deficits and "poor economic management" of the federal Liberal government that will be seeking a second mandate.

Story continues below advertisement

"We run on economy. We run on economic matters," she said.