By how much do the Conservatives need to be ahead to win?

Just closing the gap will not be enough for Erin O'Toole

A little over a week into this election campaign, it isn’t going quite as expected for Justin Trudeau and the Liberals. Rather than being on track for the majority government they failed to win in 2019, the Liberals instead need to spend a bit more time thinking about how to avoid losing the election outright.

That’s not to say the Liberals aren’t still favoured — they are. They lead in most polls and the regional distribution of their support gives them a cushion in the seat count.

But as the margin between the Liberals and Conservatives narrows, more and more polls are going to be published showing the two parties deadlocked. And some will even show the Conservatives in front for the first time since the beginning of the pandemic.

It’s already happened. As of Monday, EKOS Research has shown the Conservatives ahead twice in its daily tracking polls. Forum Research also put the Conservatives in front in their election-launch-day survey and Mainstreet Research has three times already put the gap between the Liberals and Conservatives at less than a percentage point.

That’s not great for the Liberals. But the party managed to win 36 more seats than Andrew Scheer’s Conservatives in 2019 despite finishing 1.2 percentage points back in the national popular vote. And, based on where things stand today, it looks like the Liberals can still count on that seat cushion.

So what kind of lead do the Conservatives need to have in the popular vote before they can start thinking about winning the most seats?

Using the seat projection model for the Poll Tracker, it’s possible to make some estimates.

To do so, let’s do a few things:

  • We’ll swing the vote only between the Conservatives and Liberals. Every point lost for the Liberals is a point gained for the Conservatives.

  • We’ll swing the vote uniformly across the country. Every point shifted at the national level means a point shifted in each region and province.

  • We’ll assume that support for the New Democrats, Bloc Québécois, Greens and other parties remains unchanged.

Obviously, this is not what would happen in the real world. Gains by the Conservatives might come from other parties in addition to the Liberals, while the swing in support might be more dramatic in some places rather than others. But, as a thought exercise, this gives us something to work with.

In the chart below, I’ve shown the odds of the Conservatives winning a majority government, a plurality of seats (or the most seats but not a majority) and the combined odds of the Conservatives emerging with the most seats, whether it is a majority or not.

As you can see, the odds of the Conservatives winning the most seats when trailing the Liberals in the popular vote is quite low, at worse than one-in-five when trailing by two or three points and just one-in-four when behind by a single point.

At a tie, the Conservatives still only have a 30% chance of winning the most seats, and virtually no chance of winning a majority government (naturally).

With a three-point lead over the Liberals, the Conservatives still have just a 48% chance of winning the most seats — a toss-up. By comparison, the Liberals have a roughly 86% chance of winning the most seats with a three-point lead, and even a one-in-three shot at a majority, compared to a one-in-20 shot for the Conservatives.

It’s only when the Conservatives get to a lead of five or six points that their chances of winning the most seats gets out of toss-up territory. Once we start getting to a lead of seven points, the thought exercise starts to fall apart — we’re stretching the current electoral landscape too much.

But this exercise shows that until the Conservatives get to a lead of at least three points, they would not be the favourites to win the most seats. What the NDP does in this scenario doesn’t matter much — if the Conservatives were ahead by three points thanks to the Liberals shedding support to the Conservatives and NDP equally, the Conservatives’ odds of winning the most seats would be about the same.

Where the gains come from matter

Of course, if the Conservatives do see an uptick in the polls it is unlikely to occur uniformly across the country. They might get a big bump in Alberta and Saskatchewan and less of a surge in Ontario, or vice versa.

But how any gains in support for the Conservatives differ from one region to the next makes a huge difference.

To take an extreme example, if the Conservative-Liberal swing took place only in Western Canada, moving into a tie with the Liberals in the national popular vote would give the Conservatives only a 25% chance of winning the most seats — worse than the 30% chance they’d have if the increase was uniform. If, instead, the swing took place only in Ontario, moving into a tie in the national vote would give the Conservatives a 34% chance of winning the most seats.

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A three-point national lead driven by a Conservative surge in Western Canada would only give the Conservatives a 39% chance of winning the most seats.

A three-point national lead driven by a Conservative surge in Ontario would instead give the Conservatives a 61% chance of winning the most seats.

This is why looking at where shifts in support are coming from matters. If the Conservatives re-gain lost support in parts of Western Canada and move into a close race with the Liberals in national polling, Erin O’Toole’s chances of becoming prime minister will be not much better than Andrew Scheer’s were in 2019.

If, instead, the Conservatives are able to see a surge in battlegrounds like Ontario, Quebec and British Columbia — enough to shift the electoral landscape and level the playing field — the Liberals’ seat cushion might get taken out from under them.