The latest polls suggest the province that almost single-handedly gave Stephen Harper a majority government in 2011 could see a tight contest between the Conservatives and Justin Trudeau's Liberals in 2015.

Though the Liberals still lead in ThreeHundredEight's weighted polling averages in Ontario with 38 per cent support, that puts them only two points up on the Conservatives. In the past seven polls carried out in Ontario, the Liberals have registered 40 per cent or less in all of them — and that after managing 40 per cent or more in 10 of the previous 12 polls.

The latest poll from Ipsos Reid, which sampled more than 8,000 people nationwide and over 2,000 in Ontario alone, put the two parties dead even at 37 per cent apiece.

The New Democrats trail in third place with 20 per cent in the weighted average, and have shown little life in Ontario since slumping in May. The Greens are in fourth with five per cent support.

Support appears to be shifting in Ontario, and the consequences could be significant. In September, the Liberals enjoyed a 10-point lead over the Conservatives in the polling average with 43 to 33 per cent support, enough to ensure a healthy share of the 121 seats up for grabs in the province next year. But with the gap narrowed to just two points, many seats could be decided by very slim margins.

Ontario is certainly the most important prize in 2015. The Conservatives won 73 seats there in 2011, a gain of 22 over their performance in 2008 and an increase that accounts for the party moving from minority to majority status in the House of Commons.

The last time the Liberals won an election, in 2004, Ontario was responsible for sending 75 Liberal MPs to Ottawa, and during the Jean Chrétien years the party nearly swept the province in every riding.

So the stakes could not be higher for Trudeau and Harper in Ontario. While the federal election could be decided in the province, it could be the Greater Toronto Area that decides which way Ontario swings.

The poll from Ipsos Reid shows how close things are in the region. After winning Toronto by only a handful of points in 2011, the Liberals are again in a strong position there with 46 per cent support, 20 points up on the second place New Democrats. But in the wider 905 area code that surrounds the city, the Conservatives hold a narrow four-point lead over the Liberals, with 41 to 37 per cent support.

Trudeau, Harper and Wynne

Justin Trudeau, left, joined Ontario Premier Kathleen Wynne for a campaign stop in Toronto in May during the provincial election. (Nathan Denette/Canadian Press) While voting intentions for the two parties may be moving to a tie provincewide, Trudeau does hold a narrow personal advantage over Harper. The most recent polls have shown the Liberal Party leader enjoying a higher approval rating in Ontario than the prime minister, and the latest survey by Léger found Ontarians narrowly preferring Trudeau over Harper for the top job.

Nevertheless, the popularity contest between the two leaders remains close enough that it would not take much to flip the results.

It puts into some context the ongoing spat between Harper and Ontario Premier Kathleen Wynne. The prime minister might be calculating he has more to lose than to gain i n meeting with Ontario's Liberal leader, though the polls suggest he is taking a risk.

While the Ontario Liberals are still relatively unpopular outside of the GTA, Wynne does boast better personal numbers than Harper in the province. Her latest approval ratings were a few points up on the prime minister's, while Nanos Research recently found that she was the top choice of 45 per cent of Ontarians as the best person to be premier. That is up significantly from the 32 to 34 per cent support she had in the spring.

In any case, unless federal support shifts dramatically it appears likely Ontario will deprive Harper of the majority he won in 2011, rather than renew it. But as long as the Conservatives continue to put pressure on the Liberals in the province, and in particular in the seat-rich area around Toronto, the prospects of a Trudeau victory in 2015 will also be greatly diminished.

ThreeHundredEight.com's weighted poll averages include all publicly released polls, weighing them by date, sample size, and the pollster's track record. Click here to read about ThreeHundredEight.com's methodology. The sample size, field dates, and methodologies of the polls included in the average vary and have not been individually verified by the CBC.

The poll by Ipsos Reid for Global News was conducted between Nov. 10 and Dec. 1 and interviewed 8,268 Canadians via the Internet. As the poll was conducted online, a margin of error does not apply. Ipsos Reid reports a 'credibility interval' of +/- 1.2 per cent, 19 times out of 20.

The poll by Nanos Research was conducted between Nov. 14 and 16 and interviewed 503 Ontarians via telephone. The margin of error associated with the survey is +/- 4.4 per cent, 19 times out of 20.