OTTAWA -- Marjory LeBreton has long been a force to be reckoned with on Parliament Hill. A retired senator, she's been deeply involved in Canadian conservative politics since working as a secretary for John Diefenbaker.

Now, the long-time insider is backing Kevin O'Leary's outsider bid to lead the party she's been a part of for more than 50 years.

"We need someone to shake this place up. We need someone to shake up the country and also the party. We've got to re-engage the party," LeBreton said over coffee in a shop a few blocks from Parliament Hill.

Last fall, with her "favourite candidate" Stephen Harper not in the race, the former Senate government leader was speaking with contestants and attending their events.

LeBreton took a meeting with O'Leary at the request of Mike Coates, O'Leary's campaign chair and a long-time Conservative. They met one-on-one and she says she was impressed with O'Leary's bluntness and what she calls his fresh approach. She also likes that he's a moderate conservative.

"We have to expand our base, and beyond that, we have to attract people who will never be the part of any political base," LeBreton said. "They basically will make their decisions based on the policies of any given party in any given election."

For O'Leary, that means appealing to millennial voters like his daughter, who told him she would campaign against him if he didn't support gay and transgender rights, as well as abortion rights. He told CTV News last February that his daughter voted Liberal in the 2015 election.

That could put him at odds with some of the party's social conservative base, who have a number of candidates from which to choose among the 14 running to be the next leader.

'I'm part of our base'

Jenni Byrne, a strategist and campaign manager under former prime minister Stephen Harper, told CTV's Question Period earlier this month that O'Leary is the candidate who would least be able to maintain the party's unity following the leadership.

Byrne said that while O'Leary is sometimes compared to U.S. President Donald Trump, a key difference is that Trump knew his base very well, while she believes O'Leary doesn't.

"He has dismissed the war on terror, he's insulted the military, so he's coming in as someone completely the opposite," Byrne said.

LeBreton disputes that notion, citing a number of provincial and federal politicians working on O'Leary's campaign, including former Ontario Premier Mike Harris and former Conservative caucus chair Guy Lauzon.

"I'm part of our base. I like Jenni, but -- not to dwell -- Jenni's been out of it for a couple of years. She's trying to put the party and Stephen Harper in a silo that they were never in. I just don't agree with that. The party is a big tent party."

Kevin O'Leary

While LeBreton's declared favourite candidate isn't running again, two of the Conservative leadership contestants have been compared to him. Saskatchewan MP Andrew Scheer has acknowledged the views of social conservatives while -- like Harper -- maintaining debates like gay marriage and abortion are settled, and Ontario MP Erin O'Toole has rolled out extensive policy.

For someone so supportive of Harper, O'Leary seems a surprising choice for LeBreton. The link seems to be their economic credentials.

"I think more and more when some of these people get over their Harper-hating, will appreciate what a strong steward of the economy he was," LeBreton said.

"The party is strong right now because of Stephen Harper, and so I just think now it's time to build from that, and I think Kevin can and will do it."

'People have underestimated' O'Leary’s campaign

It seems LeBreton isn't the only one who feels that way: O'Leary is considered a frontrunner in the leadership race, with his campaign saying it's raised more than $1 million since he joined the race in January and sold more than 35,000 memberships for the May 27 vote.

LeBreton says it's important to emphasize the campaign is "a bottom-up, not top-down" organization.

"I think people have underestimated the strength of Kevin O'Leary's campaign," LeBreton said.

Conservative party leadership debate

"[Campaign manager Chris Rougier] has built an organization at the provincial and the riding level, so when we sold those 35,000 plus memberships, they're pretty nicely spread across the country."

Rougier worked for the Conservative Party when Harper was leader, running voter contact and voter relations.

O'Leary hasn't promised to stick around Parliament Hill if the Conservatives don't win the next election, leading detractors to argue he isn't serious about the leadership. Other possible contenders are said to have refrained from running for the leadership because they expect the Liberals to win re-election in 2019.

LeBreton has a strong reaction to the assumption the next election is unwinnable, pointing to her experience campaigning against Prime Minister Justin Trudeau's father.

"I practically strangle them on the spot," she said. "I travelled with [Robert] Stanfield in 68. Trudeaumania was sweeping the land. Women were swooning, [Pierre Trudeau] was diving into swimming pools... four years later, we came within two seats of beating him," she said.