Lisa Raitt is one of the Conservative Party’s leading lights: lawyer, business executive, the best cross-examiner at the SNC-Lavalin hearings, minister in the Harper government and deputy leader of the Opposition since 2017. A sharp politician without social conservative baggage, it’s been widely speculated that, if she’d been leading the party rather than Andrew Scheer, the Conservatives might now be forming government.

But riddle this: On Oct. 21, Ms. Raitt lost the Milton, Ont., seat she has held since 2008. Not only did she lose, she went down to defeat by a wide margin.

There were many factors at play, including that she was running against a Liberal candidate with star power, Olympian Adam van Koeverden. But there was something deeper working against Ms. Raitt and the entire Conservative Party.

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Over the past decade, her riding has been changing and growing. As the Greater Toronto Area’s population has boomed, Milton has welcomed large numbers of new residents in new neighbourhoods, transforming it from a more rural place to one that is increasingly suburban and multiracial. Milton is but one example of a process happening across the country.

And that is a problem for the Conservatives. As a glance at a map of the election results shows, the more urban, compact and dense a riding, the less likely it is to vote Conservative. There’s an inverse correlation between living close to your neighbours and voting Conservative.

It’s deeper than Andrew Scheer: The root of the Conservative Party’s failure to launch, Part 1

It’s hard to overstate how big of an issue this is for the party. Canada’s cities and suburbs are growing. Rural Canada is shrinking.

The Conservatives did make some progress is urban Canada in 2019, picking up a handful of ridings in suburban Vancouver, and in Calgary and Edmonton.

But outside of the West, the Conservative brand faces strong urban headwinds.

In Greater Montreal, which has as many people as Alberta, there are zero Conservative seats and zero ridings the Conservatives came close to winning. The nearest blue seat is far down the Trans-Canada Highway, in rural Ontario.

In the city of Toronto, with more people than Atlantic Canada, there are also zero Conservative seats. The Tories were a distant third in many ridings, and in those where they finished second, they needed a telescope to see the podium. The Conservatives’ main contribution in Toronto was to help the Liberals, who successfully used the threat of Conservative government to push New Democrat supporters to vote strategically – for the Liberals.

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And across the GTA, there are but a handful of Conservatives. The GTA is the key to national election victory because, with the same population as the three Prairie provinces combined, it has a lot of voters and a lot of them are believed to be in play.

However, many of those in-play voters in the suburban 905 region ended up shifting away from the Conservatives and to the Liberals, not the other way around.

Take Ms. Raitt’s constituency. In 2011, it and the surrounding ridings were all blue. But Milton is in one of the fastest- growing areas of Ontario and, to account for all those new people, new seats were created prior to the 2015 election. The district Ms. Raitt first won in 2008 was divided up among five different ridings. In 2015, Liberals won four of them.

Last week, the Liberals won all five, and by considerably wider margins than four years earlier.

The Conservative Party has a demographic problem, and it has to think hard about how to address it. It cannot hope to win government solely by motivating a rural and Western base, and then counting on vote-splitting among Liberals, New Democrats and Greens. Nor can Conservatives hope to form government without capturing a big chunk of the vote in the fast-growing parts of urban and suburban Canada, particularly in Ontario.

That means Conservatives can’t win unless they can offer something more than denial on climate change.

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They can’t win unless they can offer something better than evasion and obfuscation when they produce a platform that promises spending cuts.

And they can’t win unless they rethink their faith-based deficit orthodoxy, and accept a more realistic definition of fiscal responsibility.

More on all of that, later this week.