OTTAWA -- Former Conservative leadership candidate Kevin O'Leary says quitting the race was the right thing to do because he wouldn't have been able to deliver a majority government for the party.

"It would have been selfish to just go for the leadership and not deliver the mandate that I promised. I said if I can't deliver a majority mandate, fire me," O'Leary said in an interview with Evan Solomon, host of CTV's Question Period.

The celebrity businessman was the last person to join the race, in mid-January. He spent 99 days travelling the country and jetting back and forth to the U.S. as he maintained his profile and business interests south of the border. After ending his leadership bid, O'Leary said it was the hardest thing he'd ever done. He also said that despite the work he put in over the three months he was in the race, he couldn’t drive up his popularity in Quebec -- a province he felt was vital to winning a federal election.

O'Leary threw his support to Quebec MP Maxime Bernier, who polls suggested was his chief rival. He says Bernier has the best chance of forming government, based on his ability to win 20-30 of Quebec's 78 seats. He also says the two agree on nearly every policy, with the exception of whether to end Canada's supply-managed dairy system.

"You have to understand the delicacy of that ballet -- half-art, half-science -- on delivering a majority mandate," O'Leary said.

"I love the passion of politics, but it's really driven by the numbers."

Former Conservative strategist Jenni Byrne, who ran the party's last two election campaigns, called O'Leary's assertion on Quebec "a convenient excuse" for him to drop out.

"It's a narrative that Max is going to want to push, but in last eight general elections, Quebec has only voted twice with the [party that won] government," Byrne said.

"I think it makes for a convenient argument, but it goes to the fact that he [O'Leary] actually fundamentally doesn't understand politics in this country."

While O'Leary and Bernier say they're in sync on most issues, they differ on whether Canada is embarking on a trade war with the U.S.

"I will represent our country in the NAFTA trade wars," O'Leary said.

Bernier, on the other hand, disagreed with the assertion Canada and the U.S. are locked in a trade war.

"I don't believe that. I believe it's part of a negotiation and I believe that we'll have a good deal because it will be good at the end for Canada and for America, [and] it will be good for both [countries'] consumers," Bernier said.

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