The Conservatives have widened their lead over the New Democrats over the last four months, taking advantage of an NDP slide that has gone almost unchecked since the opposition party led in national voting intentions in June of last year.

A weighted blend of polls suggests that the Conservatives currently have the support of 35 per cent of Canadians, a gain of one point since the beginning of October. The New Democrats have fallen two points since then to 29 per cent, while the Liberals have held steady at 23 per cent support. The Bloc Québécois and Greens round out the list with six and five per cent support, respectively. (Read the infographic)

The numbers for the New Democrats have soured slightly over the last few months, as the party has scored under 30 per cent in eight of the last 13 national polls. By comparison, in the 33 previous polls stretching back to Thomas Mulcair's convention victory at the end of March, the NDP was given 30 per cent or more of the vote in all but one survey. The Conservatives have only experienced a small uptick over that time, taking the lead more by default than due to any major surge in support. But that they hold a lead is virtually beyond doubt: the odds that the polls are wrong about it is only about one in 20.

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Nevertheless, Stephen Harper is still in no position to win a majority government. With these levels of support, the Conservatives would likely take about 144 seats, 11 short of an outright majority (but two more than they were estimated to be capable of winning in October). The New Democrats have taken a hit, as they would likely win some 89 seats instead of the 101 they currently hold or the 99 they could have won in October. The Liberals and Bloc Québécois have both benefitted, with the Liberals in a position to win about 63 seats and the Bloc upping their total to 11 if an election were held today. The Greens have enough support in British Columbia to hold on to their one seat.

This would potentially put the opposition in an awkward position, as due to the NDP's continuing dip in Quebec the Bloc Québécois would occupy enough seats to hold the balance of power. The NDP, Liberals, and Greens would together command just 153 seats, though that number is close enough to the majority threshold as to be within the margin of error. If these levels of support were replicated on election night in 2015, the House would be almost equally divided. With the proposed boundaries for the 338-seat electoral map, the Conservatives would likely win 157 seats to 92 for the NDP, 73 for the Liberals, one for the Greens, and 15 for the Bloc Québécois.

Regional shifts

Changes in regional support were most consequential in central and eastern Canada. In Ontario, the Conservatives increased their support to 38 per cent, while the NDP and Liberals each dropped a point to 29 and 26 per cent. This would be enough to give the Tories 61 seats in the province, three more than in October but still well below the 73 the party won in Ontario in 2011.

Quebec continues to be increasingly divided between the four parties, as the New Democrats dropped two points to only 31 per cent support. The Bloc Québécois was unchanged at 25 per cent, little more than they got in the last election, while the Liberals were up one point to 24 per cent. The Conservatives were unchanged at 16 per cent, but due to the NDP's drop could increase their representation from five to eight MPs in the province. The New Democrats would lose almost 20 seats in Quebec at these levels of support, with the Liberals picking up 10 and the Bloc seven.

The most dramatic shift occurred in Atlantic Canada, where the Liberals have picked up 11 points since October to lead with 39 per cent. The Conservatives have held steady at 30 per cent while the New Democrats were down 10 points to 28 per cent. The Liberal leadership race is the likely cause of the party's resurgence in the region, as polls routinely show that a Justin Trudeau-led party gets its biggest boost in Atlantic Canada. After winning 12 seats in the region in 2011, these numbers would bump them up to 17.

The Conservatives maintained their wide lead in Alberta and the Prairie provinces, with 62 per cent support in the former and 44 per cent in the latter. The NDP has dropped three and two points, respectively, to fall to 18 and 31 per cent, while the Liberals were up three points to 18 per cent in the Prairies. There is some scope for seat swaps, however, as the narrower gap between the Tories and NDP in Saskatchewan puts several seats at play, particularly with the new boundaries that create a handful of urban ridings in Saskatoon and Regina. The NDP could win as many as eight seats in Saskatchewan and Manitoba with this level of support, up from only two in 2011.

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British Columbia remains a close race between the Conservatives and New Democrats, with the Tories unchanged at 38 per cent and the NDP up one to 35 per cent. The provincial election scheduled for May 14, in which the New Democrats are heavily favoured, could have some federal repercussions over the next few months.

The Liberal leadership race that comes to a close in April is likely to have even more of an impact. Polls suggest that if Mr. Trudeau wins, as is widely expected, the Liberals could receive a significant boost in support. However, they also show that the party's potential gains have lessened since Mr. Trudeau's campaign launch in October and the polls have been relatively stable for some time. The probability that the three parties will be in the same position in four months as they are today is strong.

ThreeHundredEight.com'svote projection model aggregates all publicly released polls, weighing them by sample size, date, and the polling firm's accuracy record. The seat projection model makes individual projections for all 308 ridings in the country, based on the provincial and regional shifts in support since the 2011 election. Projections are subject to the margins of error of the opinion polls included in the model, as well as the unpredictable nature of politics at the riding level.

Éric Grenier writes about politics and polls atThreeHundredEight.com.