In our media-dominated world there is a principle that politicians ignore at their peril: you could offer the most imaginative and necessary policies and competent people to implement them, but without marketing they won’t sell.

This dictum is at the core of Susan Delacourt’s comprehensive survey of how marketing, polling, and advertising came to play a dominant role in Canadian politics, including the work of such legendary figures as Dalton Camp and Allan Gregg for the Conservatives and Martin Goldfarb for Liberals in keeping their teams in power.

In this revised edition of Shopping for Votes (Douglas & McIntyre, 362 pages, $24.95), published in 2013, the Ottawa-based journalist has added two chapters on how a relatively inexperienced Justin Trudeau came from a third-place standing in the House of Commons to defeat the “extremely effective, consumer targeted politics” of Stephen Harper’s Conservatives.

The promise of “sunny ways” with the media-friendly, fresh-faced Trudeau came as a welcome change after almost a decade of the dour and combative Stephen Harper and the imposition of a new ideological agenda on the country.

Secondly, the incisive debating style of NDP leader Thomas Mulcair and the party’s campaign strategy of sounding “responsible” – not promising huge and costly initiatives associated with big-government socialism – failed to build on the goodwill and official Opposition status under Jack Layton, who died shortly after the 2011 election.

Delacourt takes us back to the pre-campaign period when the Conservatives kicked off their media onslaught with prime-time ads ridiculing Trudeau as “just not ready” because being prime minister is “not an entry level job.”

The ad was produced after years of focus groups and reflected what the Conservative plotters felt was a winning message: though people liked Justin Trudeau, they had reservations about his capacity to run the country.

However, as Delacourt notes, while Harper and his team were skilled at using advertising, Trudeau was no slouch in that department. He had been at the heart of image-making since the days he was bundled in his father’s arms, to the delight of the media.

Delacourt credits Liberal operative David Herle with arguing for months that the “just not ready” charge had to be met head on by the Liberals. One hot summer day, the Liberal ad crew descended on a park near Parliament Hill to film the response.

It turned out to be extraordinarily effective, with Trudeau walking toward the camera, looking into the lens and saying, “Stephen Harper says I’m not ready. I’ll tell you what I am not ready for.”

Trudeau goes on to list all the things he would be that Harper was not, and then proclaims: “I’m ready to bring real change to Ottawa.”

It was tested in focus groups and the reaction was so positive that one Liberal backroomer praised it as “probably the most effective ad I’ve ever seen in terms of undoing or changing opinions of people.”

In another important step in image building, Toronto ad exec David Rosenberg proposed depicting Trudeau tackling middle-class stagnation by filming the young leader climbing upward on a downward moving escalator.

When it came to content, Mulcair handed the Liberals a pathway to a possible answer to the downward spiral, when he told a Hamilton audience his first budget would be a balanced budget – the kind of message a social democrat must proclaim to calm fears about deficits and higher taxes.

Remarkably, Delacourt notes, as recently as July that year, Trudeau said exactly the same thing. But on hearing what Mulcair had to say, the Liberal strategists saw an opportunity to differentiate him from the NDP, filming the ad again with him on escalator as it grinds to a halt,and Trudeau saying: “Mulcair promises more cuts. Now is not the time for cuts.”

He followed that new policy thrust with a pledge the Liberals would run a modest deficit if elected, saying “now is the time to invest in the projects our country needs.”

He was certainly not promising revolution, but it was enough to undercut the NDP’s message to left-leaning voters and a way to clearly differentiate him from the Conservative approach that less government intervention is more.

Trudeau said later he told his wife Sophie: “People will look back at today as the day we won the election.”

It was, Delacourt concludes, “an audacious form of rebranding for the Liberals,” and an example of the fascinating material she’s gathered in this insightful examination of a major event in our history.

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