She was seemingly undaunted by making the leap from her only electoral experience — two sacrificial-lamb races against late NDP leader Jack Layton in the Toronto-Danforth riding — to pursuing the leadership of what was once Canada's natural governing party.
To that point, the main reason most people might have recognized her name was due to her relationship with former prime minister Pierre Trudeau and the daughter she had with him in 1991. She had never commented publicly on that part of her life.
But in January she published a short e-book, Unscripted, about her background, her experience as a constitutional advisor fighting the Meech Lake and Charlottetown accords and her relationship with the elder Trudeau.
The liason lasted 15 years and she would have liked to marry him, but he balked at the 37-year age gap between them. The book is full of photographs of happy times with Trudeau and their daughter Sarah, taken mostly at his chalet in the Laurentians.
The timing of the book is insignificant, she suggests.
"I do believe people are entitled to know enough about my personal and professional life to see why I'm running this race," she said in a telephone interview.
In other media interviews she appears defensive, refusing to comment on the irony of running against Trudeau's son, whom she barely knew during her long liason with his father.
"It is what it is," she says, and little more. The two families were separate, she writes in the book, and Trudeau didn't want her to move to Montreal after she had Sarah.
The book depicts her charmed childhood, a house in Ottawa's tony Rockcliffe neighbourhood, private school, a cottage at Meech Lake. As a university student, Coyne comes across as adventurous and curious, the founder and captain of Oxford University's first female hockey team, a student backpacker who travelled through Russia and the Middle East.
Later, after law school and different jobs, there might have a launch of an early political career, but, at age 30, the relationship with the 67-year-old Trudeau deterred her from seeking a Liberal nomination in Toronto. She was close to 50 before she tried again.
A policy wonk
Over the phone, Coyne speaks so quickly it's hard to catch every word, the talking-as-fast-as-you-think style of a policy wonk who's mapped out every position.
She is in favour of a carbon tax, but makes it clear it would be nothing like former Liberal leader Stéphane Dion's "green shift" that would have created an eco-tax on carbon while reducing personal and corporate income taxes.
Instead, Coyne said, "The revenues for the tax would go to the province in which they were generated. So, it is not redistributive.
"There will be, of course, a lot of revenues generated from this kind of tax in Alberta and Saskatchewan. It's the right way to go."
On electoral reform, Coyne suggests a committee that would travel across the country after the next election, seeking ideas about how to change the way federal politicians are elected. Once the option with the most consensus was selected, there would be a national referendum. "Go to the people on this, people want a change," she said.
Coyne is proposing a federally-led drug program, a criminal justice council that would advise government about proposed changes to the Criminal Code and legalization of marijuana.
She's critical of the government's approach to China, especially on the takeover of Calgary-based Nexen by China's CNOOC.
"I would have been much more upfront in terms of negotiations and got more advantages out of it. And I'm confident we could have done it. You never know until you try. And Newfoundland has done it in their natural resource sector, and Norway, that's the secret behind Norway."
'It doesn't cost a lot to rent a car, and stay with people'
When asked if she can continue her campaign after raising so little money, she said, "We have a very low-spending campaign. It doesn't cost a lot to rent a car, and stay with people."
Elections Canada filings show Coyne had raised the least amount of money of any of the candidates by the end of last year, about $16,000 compared to Trudeau's total of more than $670,000.
She raised the $75,000 entry fee from loans, the maximum she can borrow. Campaign costs must come from money that's donated.
Asked how many supporters she has signed up, Coyne said, "You know what? I haven't paid any attention, and I'm not worried about signing up my own supporters. The supporter pool is open to anyone."
On her website, Coyne warns Liberals to stay away from "vague platitudes and empty sound bites," but denies she is taking a veiled shot at Justin Trudeau.
"I think Canadians want an intelligent conversation," she said. "I've been to a number of editorial boards, and without exception they say at the end that I'm the first politician that's been there that doesn't talk in talking points."