Incumbent mayor Brian Bowman faces an unusual if not unique challenge in this election: Winning a second term with the support of Winnipeggers who voted against him four years ago.

In 2014, the privacy lawyer won a landslide victory in the wide-open race to succeed Sam Katz as Winnipeg's mayor.

He did so by defeating former NDP MP and MLA Judy Wasylycia-Leis, future Liberal MP Robert-Falcon Ouellette and former city councillor Gord Steeves, a one-time Liberal who donned provincial Progressive Conservative colours before tacking hard to the right in an ill-fated campaign.

A big component of Bowman's appeal in 2014 was his status as a political outsider at a time when Winnipeggers grew tired of the real-estate and capital-procurement scandals that afflicted Katz's city hall.

Bowman also enjoyed support from volunteers from a wide variety of political backgrounds. But the lawyer himself was a longtime provincial Progressive Conservative prior to his run for public office. Bowman also was considered a potential Manitoba PC leadership candidate before Brian Pallister claimed that job.

Based on Bowman's political affiliation, which was publicized widely during the 2014 campaign, it's not a big stretch to assume some of his support came from Progressive Conservative voters.

A quick look at the voting data from 2014 confirms this.

For starters, take a look at the polling subdivisions won by the mayoral candidates who claimed victory in Winnipeg polls that year. Ouellette, a political neophyte in 2014, won some inner-city neighbourhoods. Wasylycia-Leis, the long-time NDPer, won a number of neighbourhoods in Winnipeg's northwest.

Bowman won practically all the outlying polling subdivisions in 2014 in western, southern, eastern and northeastern Winnipeg.

In the 2014 municipal election, Brian Bowman won most polling subdivisions in western, southern and eastern Winnipeg. Judy Wasylycia-Leis took the northwest and Robert-Falcon Ouellette won some polls in the inner city. (CBC News Graphics)

Bowman's success in outlying areas of Winnipeg in 2014 is just as apparent if you remove Wasylycia-Leis and Ouellette votes from the data visualization.

The polling subdivisions where Bowman received the highest proportion of the vote in that election are not just in the west, south, east and northeast of the city, but in the northern fringe as well.

In 2014, Brian Bowman received most of his support from Winnipeg residents living outside in suburban residential neighbourhoods. In broad strokes, the polling subdivisions where Bowman's support was strongest overlap with polls that voted Progressive Conservative in 2016. (CBC News Graphics)

If that pattern of voting looks familiar, it may be because you saw it more recently: say, in 2016, when Pallister's Progressive Conservatives won a landslide election victory of their own.

In 2016, Manitoba PCs won all the ridings in a crescent of Winnipeg that begins west of the inner city and curls around the southern, eastern and northern flanks of the Manitoba capital.

The blue Winnipeg ridings voted Progressive Conservative in Manitoba's 2016 provincial election. (CBC Interactives)

In other words, there appears to be a very strong overlap between Winnipeg neighbourhoods that supported Brian Bowman in 2014 and the neighbourhoods that supported the provincial Progressive Conservatives in 2016.

Many Bowman voters in the last civic elections appear to be Progressive Conservative voters in the last provincial race.

Assuming some of this political geography remains valid in 2018, Brian Bowman likely would not face any challenge in another race where his two strongest opponents are a longtime NDP politician and a nominal Liberal.

But that is not the case in 2018, when a CBC-commissioned poll conducted by Probe Research suggests Bowman's only challenge comes from another conservative-affiliated politician, Jenny Motkaluk.

According to that online poll of 600 adults, conducted in late August, Bowman and Motkaluk are the only candidates to enjoy the support of more than one per cent of Winnipeg voters.

The poll placed Bowman's support at 22 per cent, with Motkaluk enjoying 11 per cent. The undecided vote was enormous: 57 per cent of Winnipeggers don't know who to vote for on Oct. 24. The margin of error in these results is four per cent.

Mayor Brian Bowman is Winnipeg's preferred candidate, but the undecided vote remains high, Probe Research suggests. (CBC News Graphics)

Now you may be wondering where the problem lies for Brian Bowman. After all, Bowman is a well-known incumbent mayor in a city where no incumbent mayor has lost an election since 1956.

As well, few voters outside of Mynarksi ward — where Motkaluk ran for council and lost to Ross Eadie in 2010 — have ever heard of the business-development consultant.

Bowman a candidate of the centre-left?

The problem is it appears voters in this city no longer see Brian Bowman as a conservative candidate. And it also appears that is how they see Jenny Motkaluk.

According to the same Probe Research poll, Motkaluk enjoys the support of 48 per cent of Winnipeggers who voted Progressive Conservative in the 2016 provincial election. Bowman, on the other hand, enjoys only 37 per cent support from 2016 Tory voters, according to the poll

That wouldn't appear too damning until you see who 2016 NDP voters support in this year's mayoral race. The Probe poll suggests 80 per cent of the Winnipeggers who voted for Greg Selinger's NDP in 2016 support Brian Bowman in 2018, while only 17 per cent of NDP voters in 2016 would vote for Jenny Motkaluk.

Probe Research president Scott MacKay said these numbers jumped out at him even though the sample size for political subgroups is small and the margin of error is higher.

"I think that is interesting because [Bowman] didn't set out to establish himself as a candidate on the progressive left. As you recall, when he was elected, he was running against a former New Democrat MP. For whatever reason, he seems to be the choice of that group of people," MacKay said in an interview.

"He didn't really switch. I think the voters have decided, themselves, in this kind of binary world, where there's somebody on the right and maybe somebody more in the centre, that he will be their guy."

'No right- or left-wing way to combat mosquitoes'

Bowman, for his part, rejected the idea he is now the candidate of the centre-left.

"I have governed for all Winnipeggers," Bowman said on Friday at his campaign office, before listing off achievements that would appeal to fiscal conservatives, such as a minuscule spending increase in the 2018 budget and a successful effort to slow the growth in spending on public-sector union contracts.

"If you want to serve Winnipeggers, you have to be able to represent a broad coalition of Winnipeggers. There's no right- or left-wing way to combat mosquitoes or clear snow or pick up garbage."

While that statement sounds logical, a quantitative assessment of Bowman's first term as mayor suggests there is a rift between Brian Bowman's political philosophy — a truly progressive form of conservatism that incorporates urbanism and a deep regard for Winnipeg's Indigenous community — with a more populist form of conservatism.

Bowman's push for growth fees annoyed developers, a small but powerful constituency that could park political donations in Motkaluk's camp.

More significantly, the incumbent mayor's support for reopening Portage and Main to pedestrians is at odds with the desires of most Winnipeggers, especially in outlying areas of the city where he received so many votes in 2014.

It was clear early in this campaign that Motkaluk has been trying to separate Bowman from his 2014 support base by highlighting the incumbent's support for reopening Portage and Main and rapid transit.

It is possible, if not probable, her strategists overlaid the very same 2014 municipal voting data with the 2016 provincial data you just looked at a few paragraphs ago.

If Motkaluk does become the definitive candidate of the right and Bowman becomes the centre-left candidate in the eyes of Winnipeg voters, it does not mean the incumbent will lose his job as mayor.

What it does mean is he must win re-election with the support of people who voted against him only four years ago.

That is a re-election challenge few mayors have ever faced.