Two events proved to be significant turning points in the election campaign. One was the rise of the Bloc Québécois after the first French-language debate, which "fundamentally shifted the dynamics," according to Dan Arnold, the Liberal Party's pollster.

The other was the moment that the electorate "definitely woke up" — the news that the prime minister had worn blackface on multiple occasions before entering politics.

Arnold, the party's director of research during both the 2015 and 2019 federal elections, discussed what the Liberals' polling was showing during the campaign in an interview on CBC's The Pollcast podcast (stream the full interview below).

The first week of the campaign showed very little engagement from voters, Arnold says, with the numbers suggesting Canadians were less tuned-in to the election than they had been in previous campaigns. But after the photos were first published by Time magazine, "the number of [Google] searches for [Prime Minister] Justin Trudeau increased fifteen-fold."

"Even on our survey, where we were asking questions about 'how much attention are you paying to the election campaign', that shot through the roof."

Arnold says that with the electorate suddenly paying attention, there was a risk that people's opinions could change very quickly. This is what made Trudeau's reaction to the scandal in the first days so significant.

"Luckily, we had focus groups scheduled for the day after in the 905 [area code around Toronto], so that was actually a pretty good way to get a quick reaction to how it was being perceived. The sentiment that really came out from the focus groups there ... was, obviously they said it was wrong and they were not happy that this had come out and that the prime minister had done this.

"But because everybody had been paying so much attention to it, they all saw the clips of the prime minister responding, they all saw his apology, and pretty much everybody thought he was sincere, thought he was genuine. Canadians are pretty forgiving. If somebody says 'I screwed up, I'm sorry,' and they mean it, people are usually going to forgive them.

"I think that is actually an interesting contrast with [Conservative Leader Andrew] Scheer," says Arnold. "When his views on same-sex marriage came out, he was slow in responding, didn't really give any self-reflection or any kind of hint that he had changed his views over time, he never really apologized for the comments that he had made."

Arnold says that the Liberals' vote numbers didn't drop in the aftermath, but "I won't say it had no impact. I think it may have left, especially with a lot of younger voters, a bit of a lingering disaffectedness, a little disappointment more with the prime minister than they may have had before."

The Bloc's 'road block' in Quebec

Public polls suggested that Yves-François Blanchet, leader of the Bloc Québécois, was the winner from the first French-language debate broadcast by TVA on Oct. 1. The internal Liberal polls were showing the same thing.

"Certainly we saw the Bloc's numbers increase significantly after that [debate]," says Arnold. "A lot of that was at the expense of the Conservative vote, because Scheer did not do very well."

But that drop in support for the Conservatives took a toll on the Liberals' own prospects of winning seats in the province.

"The realities of our electoral system are that Conservative voters moving to the Bloc actually ended up hurting us ... because then a lot of races we would have won by two or three points in the Eastern Townships ... the North Shore [around] Montreal, suddenly we were behind the Bloc because they had gone up, even if it wasn't all at the expense of our own votes there."

The Bloc Québécois made significant gains in the polls after Yves-François Blanchet's performance in the Oct. 1 French-language leaders' debate broadcast by TVA. (Ryan Remiorz/Canadian Press)

Arnold believes that was the only major shift in voting intentions that changed every other party's electoral calculations — especially his own.

"At the start of the campaign, there was definitely a path that involved us gaining seats in Quebec to get to that majority number again," says Arnold.

"If that path had a roadblock on it, there were always other paths that could have presented themselves. If the NDP and Green vote in B.C. collapsed, we could gain some seats there, or if there had been a bigger swing in Ontario than there was, that was also a path to it."

"But I think it's fair to say that the Bloc doing better in Quebec certainly made the math for a majority a lot more difficult from our perspective."

By election day, that put the Liberals on track for a minority government.

"I think our final numbers had us winning 163 seats, says Arnold, "plus or minus a pretty wide band on that but even the lower end of that band had us in the mid-140s. So, I think we were pretty confident that we were going to win. Personally, [I was] nervous because if you actually do undershoot that, then everybody is going to blame the pollster."

On this episode of the Pollcast, host Eric Grenier sits down for an interview with Dan Arnold, the Liberal Party's director of research over the last two election campaigns, to talk about what worked and what didn't during this election. 31:54

Listen to the full interview above — or subscribe to the CBC's Pollcast and listen to past episodes of the show.