Toronto could cast a decisive vote in Ontario's provincial election on Thursday. It could decide between a majority or a minority government.

The odds of a minority government are currently low: the CBC Poll Tracker estimates the chances of a majority government being elected at about 92 per cent. That's because the Liberals are projected to win so few seats that a minority government is mathematically unlikely.

More Liberal MPPs mean a higher likelihood of a minority government. And the best place for more Liberals to be elected is in Toronto.

The city has long been a Liberal bastion. The party has won the most votes and seats in the city in every election since 1999. In 2014, the Liberals took 49 per cent of the vote — a few points better than their performances in 2007 and 2011. The Progressive Conservatives and New Democrats trailed at some distance, with 23 and 22 per cent apiece.

The Liberals are the incumbents in almost all of Toronto's 25 ridings. Only two of those ridings elected NDP MPPs four years ago, and the PCs were shut out until they won a byelection in Scarborough in 2016.

But the Liberals are in serious trouble in the city and appear to be struggling to retain their 22 seats there.

According to the June 1 update of the Poll Tracker — an aggregation of all publicly available polling data — the Liberals' support has been cut by more than half in Toronto. They trail in third with 23 per cent, down 26 points from the 2014 provincial election.

Both Doug Ford's PCs and Andrea Horwath's New Democrats have benefited from that collapse, with the PCs up eight points to 31 per cent and the NDP up 18 points to 40 per cent. Half of those gains occurred in just the last week, at the expense of the Liberals.

The Greens follow with five per cent, while just one per cent of Torontonians say they will vote for another party. (Of the small parties, only the Libertarians are running in all ridings. No other small party is running even a half-slate.)

Liberal hopes for survival rest on Toronto

If the Liberals were losing support to just one party, they might have been able to hold on to one part of the city. Instead, they're poised to lose Toronto's downtown core to the New Democrats, while the Progressive Conservatives could win in the suburbs in North York, Etobicoke and Scarborough.

None of this leaves the Liberals with a lot of options.

Ontario Liberal Leader Kathleen Wynne campaigning in Toronto on Wednesday. The party entered the election holding almost all of the city's seats. (Frank Gunn/Canadian Press)

The party is still in play in the three Don Valley ridings (including Don Valley West, where Kathleen Wynne is running for re-election) and in Toronto–St. Paul's. Liberals also might be able to hold on in three-way contests in some of the Scarborough ridings.

But it's difficult to lose more than half of your support and still win seats — even in ridings that were won by significant margins in 2014. And the Liberals lack incumbents in five of their 22 seats, having already lost higher-profile former cabinet ministers like Glen Murray and Eric Hoskins. This might make it even harder to secure these ridings — particularly in the context of the recent swing in support to the NDP from the Liberals.

Horwath was in Wynne's riding on Friday asking voters to back her party to block Ford's PCs — an invitation to voters to cast their ballots strategically. The swing suggests it's a message that could be resonating in Toronto.

NDP looking to grow from the centre out

The New Democrats traditionally have been able to count on a few seats in Toronto, particularly in the downtown core along Lake Ontario. But the party might be able to expand that beachhead deeper into the city — and perhaps turn some territory orange that might otherwise have turned blue.

Those downtown ridings — Beaches–East York, Davenport, Spadina–Fort York, Toronto Centre and University–Rosedale — are poised to flip to the New Democrats. But in addition to these seats in more traditionally NDP-friendly territory, the NDP also could pick up a few other seats from the Liberals outside of the party's traditional base of support, such as Humber River–Black Creek, Scarborough Centre, Scarborough Southwest, Scarborough–Rouge Park and York South–Weston.

Ontario NDP Leader Andrea Horwath was campaigning in Toronto on Friday. The NDP is leading in the polls in the city. (Nathan Denette/Canadian Press)

In those Scarborough seats, the contest might instead be between the NDP and the PCs, considering the steep drop in Liberal support.

The New Democrats need to be competitive in these parts of Toronto. While the downtown seats might help bulk up the party's caucus, it won't be enough to put the party into government. For that, the NDP would need to win seats outside of their traditional bases of support — both inside and outside of Toronto.

If New Democrats can't flip most of the seats in Scarborough toward them, they're unlikely to win the seats elsewhere they need to form a government.

Will Doug Ford help deliver Toronto?

For the Progressive Conservatives, however, Toronto might mean the difference between a majority and a minority government.

Ford's promise to PC members when he won the leadership race in March was that he could win in Toronto. Maybe he can't take all the credit — the party was polling about as well in Toronto before Ford took over — but he does seem to be delivering on his promise.

The PCs are on track for their best performance in the city since they last formed government under Mike Harris. The PCs could take seats from the Liberals in the Don Valley and Etobicoke (where Ford is running), as well as in Scarborough and North York. The party is in range of winning between seven and 15 seats in the region — a significant increase.

Those could be important seats. The PCs are currently projected to win 72 seats provincewide (though their likely range runs from 52 to 84). If the PCs win just seven seats in Toronto, that would drop them down to 65 — just above the threshold of 63 seats needed to form a majority government.

And if they are under-performing in Toronto, they'll probably under-perform enough to fall short in at least two other seats elsewhere in Ontario. And Ford might struggle to form a government in a minority legislature if doing so means winning the support of either Horwath or Wynne.

Only once in the last three decades have the Progressive Conservatives won more than seven seats in Toronto. If Toronto surpasses that amount a second time, Ford will almost certainly become Ontario's next premier.