The sudden separation of seven MPs from the Bloc Québécois caucus could have a significant impact on the outcome of the 2019 federal election — one that far outweighs the diminished role the sovereigntist party has played on the national stage since its collapse in 2011.

The CBC's polls analyst Eric Grenier looks at how the recent Bloc walk-out will affect their chances in 2019. 3:23

The Bloc is not the same party that formed the Official Opposition in 1993, held the balance of power in minority Parliaments between 2004 and 2011 and won most of Quebec's seats in all six elections held between 1993 and 2008.

While the Bloc's potential in 2019 was always going to be largely limited to playing a spoiler role in a number of ridings and eking out some wins in three- and four-way races, its recent internal turmoil raises the prospect of another collapse in its support.

But unlike what happened in 2011 — when the New Democrats were the beneficiaries — it's the Liberals who could see their fortunes improve next year if the Bloc's dwindling support fractures even further.

The split in the party is the result of disagreements over the leadership of Martine Ouellet, a former Parti Québécois MNA who sits in the National Assembly as an independent.

Ouellet, who twice failed to win the leadership of the PQ before being acclaimed as Bloc leader in 2017, wants to have the party focus on promoting the cause of Quebec independence.

Louis Plamondon, one of seven MPs to leave the Bloc caucus, is the longest-serving member of the House of Commons and one of the Bloc's original MPs. (Sean Kilpatrick/Canadian Press)

The seven MPs who left the party — reducing the Bloc to only three sitting members, fewer than the four seats the Bloc was left with after 2011 — will now sit as a 'Quebec Parliamentary Group'. They say they will focus on defending Quebec's interests, which was how the Bloc Québécois' role was defined under former leader Gilles Duceppe.

​It isn't clear how all this will play out between now and the next federal election campaign. But if the divide is still hobbling the party in 2019 — due to a disputed leader, the perception of a party at war with itself or the presence of independent MPs running for re-election in formerly Bloc-held ridings — its effects could reverberate beyond Quebec.

The Bloc on the brink

The party's support in Quebec currently sits at 17.2 per cent, according to the Feb. 27 update of the CBC Poll Tracker. That puts the party about two points below its 2015 election performance — and 26 points behind the Liberals.

Notwithstanding the events of this week, holding the 10 seats the party won in 2015 was going to be a struggle.

The Bloc won six of them by less than five points. If an election were held today, all of their seats would be on the bubble, with decent prospects for the party in perhaps three of them.

According to the Poll Tracker, the Bloc would have only an eight per cent chance of winning the 12 seats needed to obtain official party status in the House of Commons, which gives parties more resources and privileges.

In eight of those 10 ridings, the Liberals placed either second or a strong third. Considering the Liberals have made significant gains in popular support in the province since, that would put Prime Minister Justin Trudeau in a good position to pick up all 10 seats in 2019.

Trudeau also might be in the best position to pick up any support the Bloc could lose as a result of the party's recent troubles.

Liberals positioned to take advantage

While polls suggest that Bloc voters do not look upon any of the three main federal party leaders with favour, Trudeau comes out a little better than the others.

Though the sample sizes are small, a Campaign Research poll found that 15 per cent of Bloc voters thought Trudeau would make the best prime minister. Both Conservative Leader Andrew Scheer and NDP Leader Jagmeet Singh scored four per cent.

Trudeau's approval rating stood at 27 per cent among Bloc voters in the Campaign Research poll, with 66 per cent disapproving of him. The split was 37 to 50 per cent in a recent Forum Research survey.

Again, though the sample sizes are small, the same patterns emerge in the two polls. Scheer's approval rating among Bloc voters was just 14 to 20 per cent in the two polls, compared to a disapproval rating of 31 to 40 per cent. Singh's numbers were worse: 10 to 18 per cent approval to 37 to 42 per cent disapproval.

This suggests that if Bloc voters decide to look elsewhere in 2019, they would be more likely to opt for the Liberals than either the Conservatives or New Democrats. If they decide instead to stay home, the party already in the lead — the Liberals — would benefit the most.

Bloc voters are disinclined to support someone like NDP Leader Jagmeet Singh, a Sikh who wears visible symbols of his religious faith. THE CANADIAN PRESS/Justin Tang (Justin Tang/Canadian Press)

Singh's limited appeal to Quebec nationalists

The potential the New Democrats might have had to pick up wayward Bloc voters largely disappeared with the selection of Singh as their leader last year. Polls suggest that Quebecers — and Bloc supporters in particular — are the least likely to vote for a party led by a leader wearing visible religious symbols, such as a turban-wearing Sikh.

The Conservatives might have an opportunity to pick up more nationalist-minded Bloc voters, but veering too far into identity issues could hamper the party's appeal with other constituencies.

Even before Wednesday's Bloc implosion, the Liberals were well-positioned in Quebec. Their support there could deliver them another 20 seats or more — which could make up for losses in the rest of the country, where the Conservatives are poised to make gains.

The political divide between the Liberals and the Bloc is wide, and Trudeau hasn't taken much support away from the Bloc since 2015. But if the Bloc's support splinters under Ouellet's contested leadership, it could further increase the Liberals' advantage in the province — and make their re-election in 2019 more likely.