TORONTO -- Watching Liberal incumbent Adam Vaughan move from door to door, signs stacked under his arm, his choices seem counterintuitive. He's going up to homes that already have NDP candidate Olivia Chow's name attached to the front fence.

But in the dying days of a tight campaign that began back when the hydrangeas were blooming, Vaughan is testing just how firm those initial allegiances were.

Vaughan says he started to see a discernible shift to the Liberals after leader Justin Trudeau said he wasn't afraid of running deficits in order to spend on infrastructure, including in Toronto.

"When that message dropped, it really pushed us forward. And in the last couple of weeks, I'm literally walking up the street and people with orange signs are saying 'you can change the sign for me'," Vaughan said in an interview Thursday.

"As a candidate, when that happens, it's like, ah, spring's arrived."

Spadina-Fort York is a prime example of the fierce Liberal-NDP fight that is underway in downtown Toronto, pitting marquee candidates against each other.

With the Conservatives not a threat in these core ridings, the orange and red teams are focused on building up their seat counts here in the quest to topple Stephen Harper nationally.

"In the 416 and the 905, can we build enough seats before we hit the Manitoba border, and have the western seats just put us over the top?" says Vaughan.

"It's critical from the perspective of the parties' fortunes; Toronto and the 416 are the high water mark. This seat has two big campaigns running, so it's a test of the two teams."

Vaughan and Chow both have an honest claim to the riding of Spadina-Fort York, which encompasses most of the previous riding of Trinity-Spadina. Vaughan won the seat in a 2014 byelection when Chow made an unsuccessful bid for the Toronto mayoralty. Chow took the riding in 2006, 2008 and 2011, and stepson Mike Layton is the area's city councillor.

She spent Thursday morning passing out flyers and talking to commuters about to board a streetcar, a bright orange scarf wrapped around her neck. A TTC driver wearing a Blue Jays cap asked her for a campaign button at a red light.

Chow dismisses the impact locally of the Liberal surge suggested by the polls nationally.

Trudeau's nightly stump speech has featured language markedly reminiscent of her late husband and NDP leader Jack Layton's final message to Canadians, about choosing hope rather than fear.

Then on Wednesday, Trudeau's campaign co-chairman Dan Gagnier stepped down after it was revealed he had emailed contacts in the oil sector about how to successfully lobby a new government.

It's a reminder, Chow says, that the Liberals are no progressive substitute for the NDP.

"This is the Liberal style. They always campaign like New Democrats, take our words, take our ideas, and then they govern like Conservatives," said Chow.

"Allow me to remind people of the 1995-96 budget, where health care, affordable housing, education funding was slashed. We're still feeling the impacts of those cuts -- 20 years later. Look at the homelessness crisis in this country."

Chow says the riding has a strong NDP team in Toronto, and voters recognize who the real progressive choice is.

"Those that know me tend to say, 'Olivia I voted for you many times, and I'm voting for you again, and welcome back,"' said Chow.

"Then there are those who have just moved in, fairly new in the neighbourhood...Lately I've been getting a lot of doctors and nurses that are really upset with the Ontario Liberals."

But that nebulous space that the federal Liberals are occupying this election, holding up progressive and business-friendly credentials all at the same time, could find its place in Spadina-Fort York.

Vaughan argues that the people living in condos, the children of suburban dwellers and young professionals, are wary of the NDP.

The mercurial take-up on lawn signs in the area still suggests a tight, shifting race. One home in the Portuguese-Canadian pocket of the riding displayed signs from all three major parties.

Local bar owner A.J. Abad said he hasn't made up his mind how to vote, and would even consider voting Conservative.

"Anything in terms of helping us prosper in the community. A lot of times we pay a lot of fees, we pay a lot of taxes. So anything that helps in that sense would be good," said Abad.

"I used to be strictly Liberal, but I'm open to all parties."