MONTREAL -- As NDP candidate Anne Lagace Dowson spends a recent morning greeting public transit users and chatting up patrons at a cafe in Montreal's Papineau riding, her high-profile political foe is campaigning way across the country in British Columbia.

Lagace Dowson, a Montreal journalist and commentator, was thrust into the campaign just a few weeks ago at the behest of party brass and, despite the short notice, is confident about her chances.

That her opponent happens to be Liberal Leader Justin Trudeau is of little consequence to her.

"I think Justin Trudeau is vulnerable in this riding," Lagace Dowson says during a brief break from campaigning in a riding the NDP hopes to steal come Oct. 19. "We're going to make sure we're visible in every part of the riding, that there is a viable option to the Liberals."

It's a monumental task -- not just winning a federal riding or unseating an incumbent --but knocking off a federal party leader.

Not that it can't be done.

In 2011, both Liberal chief Michael Ignatieff and Bloc Quebecois Leader Gilles Duceppe were defeated in their own ridings. The last sitting prime minister to lose a seat was former Progressive Conservative leader Kim Campbell in 1993.

The prospect of any of the three major leaders or the Green party's Elizabeth May losing is slim, says Sebastien Dallaire of Leger, a polling, research and strategic marketing firm.

The leaders all have solid teams on the ground to make up for their absences during a campaign.

"It has happened in the past but, typically, party leaders get a bump in their ridings so it would be surprising if any of the four leaders were to lose their seats," says Dallaire, especially if the polls continue to suggest a tight, three-way party race.

Three current leaders -- Trudeau, the NDP's Tom Mulcair and Gilles Duceppe of the Bloc Quebecois -- are running in Montreal island ridings while May and the Conservatives' Stephen Harper are running in B.C. and Calgary respectively.

The one exception may be Duceppe, who is in tough as he tries to regain his seat against the NDP's Helene Laverdiere.

The upset-minded candidates running in Montreal are quick to point out that Quebecers have shown in recent years they are not afraid to turf provincial leaders such as the Liberals' Jean Charest in 2012 and the Parti Quebecois' Pauline Marois in 2014.

Trudeau, who was first elected in Papineau in 2008, won in 2011 by a comfortable 4,327-vote margin, but Lagace Dowson, 56, says she's buoyed by a change in riding boundaries and a stronger NDP team on the ground.

Lagace Dowson ran and lost in 2008 to Liberal Marc Garneau in a different Montreal riding and sat out during the NDP's 2011 Quebec sweep.

She has merged her campaign with that of neighbouring NDP candidate Alexandre Boulerice, an influential member of the Quebec caucus.

Lagace Dowson isn't the only long shot in the area.

In nearby Outremont, which Mulcair calls home, lawyer Rachel Bendayan hopes the riding becomes Liberal red again.

Between 1935 and 2007, Outremont slipped from Liberal hands just the once. Since Mulcair's arrival, it has gone NDP with the party leader securing more than 56 per cent of the vote in 2011.

Bendayan's nomination in March 2014 was among the first in Canada for this fall's election. She took a leave of absence from her practice to focus full time on the campaign and estimates she's knocked on some 10,000 doors in her giant-killing bid.

"They (people) are quite in awe of my dedication, they often tell me whatever happens, I've already contributed to changing their perception of politics and politicians," Bendayan says.

Activating that dormant Liberal base will be key, says Bendayan, 35, a lifelong Outremont resident who says changing the way of doing politics means replacing the old guard and bringing a fresh perspective.

In Harper's home riding of Calgary Heritage, the Conservative leader has often garnered more than 70 per cent of the votes.

Two locals are among those vying to unseat him: musician Matt Masters Burgener is taking up the NDP mantle, while the Liberals are running family doctor Brendan Miles.

Miles, 34, says he has scaled back his medical practice to run a "serious, hard-working campaign" that has meant attending community events and knocking on thousands of doors.

"I was born and raised here and I'm from here, so this is more than just a riding to me, it's my home," Miles says. "If I'm going to do that (be an MP), I really want to represent my home."