Who had a Bloc resurgence on their federal election bingo card?

The campaign has seen one bizarre twist after another without any apparent impact on the polls — until now. This latest twist is a little retro. The Bloc Québécois, pronounced all but dead after 2011, has been reanimated and could significantly upend the election plans of the Liberals and Conservatives.

The CBC Poll Tracker shifted suddenly in its latest update, with the Bloc's gains in Quebec erasing the solid seat advantage the Liberals enjoyed over the Conservatives.

Since the beginning of this campaign, the Liberals had been favoured to win more seats than the Conservatives, regardless of which party was ahead in the national polling average. This was being driven in part by the party's enduring edge in Ontario — but it was Quebec that made the difference.

Liberal support in Quebec has hovered around the 36 per cent mark the party hit in 2015. Because of the wide gap separating the Liberals from the other parties in Quebec, however, they could count on winning about 50 seats in the province, a net gain of 10 over the last election's results.

But now, at just under 34 per cent, Liberal support is looking softer in Quebec. The Bloc, meanwhile, has picked up seven points in the last 10 days and has moved into second place in the province, with 27 per cent support.

That has dropped the Liberals into the mid-30s in the seat projection for Quebec, nearly tied with the Bloc Québécois. The Conservatives also have slipped and appear to be on track to win around 10 seats in Quebec, down from the 12 they took in 2015.

Liberals tied with Conservatives in seats

From a high of 166 seats in the national projection in the days following the French-language TVA debate, before the fallout from that contest was being registered in the polls, the Liberals have plummeted nearly 30 seats to 139. That puts them just two ahead of the Conservatives.

The close race in the national polls has now become a close race in the seat projections — meaning this election has become even more of a toss-up.

There is also now only a 25 per cent chance that either party can win a majority of seats.

The Bloc has been eating into the support of the Liberals, Conservatives and Greens in Quebec, though the seat impact has primarily been felt by the Liberals. That's because the Conservative base of support in Quebec is concentrated around the Quebec City area, where polls suggest the party still holds a lead.

Liberal Leader Justin Trudeau held a rally in Ottawa on Friday. His party is neck-and-neck with the Conservatives in national polls. (Frank Gunn / Canadian Press)

But in the rural regions of Quebec and the francophone areas in and around Montreal, the Liberals had been banking on winning seats with relatively low shares of the vote, benefiting from a vote split between the Conservatives, Bloc and New Democrats.

That logic no longer holds now that the Bloc has moved into first place among francophones and (as a consequence) in the regions that were being targeted by the Liberals. That has the potential to paint dozens of seats Bloc blue rather than Liberal red.

Not helping matters for the Liberals is the fact that the New Democrats appear to be building up some momentum of their own after a strong performance by NDP Leader Jagmeet Singh in Monday's English-language debate. After posting poll numbers that would have given them about 15 seats nationwide, they are now projected to win around 24 seats.

So the coming week could prove to be decisive. After nearly five sleepy weeks, voters are wide awake and feeling volatile. Blink and you might miss the next twist.