Getting to a Majority on the Lowest Vote Share in Canadian History
Under First Past the Post, a party can get a majority of seats in an assembly while getting well short of a majority of the popular vote. Canada’s last two majority governments, formed in 2011 by Stephen Harper and 2015 by Justin Trudeau, were won with vote shares fractionally below 40%, and this has been considered around the usual threshold in recent decades to winning majorities.
Going back through Canada’s history of majority governments, the one achieved with the smallest vote share occurred in 1997, when Jean Chrétien led the Liberals to his second majority government with just 38.5% of the popular vote. It’s unclear whether or not Mr. Trudeau can lead the Liberals to a majority government next month, but if he does so he may do so with an even smaller vote share than Mr. Chrétien.
Votes Needed to Win
Under First Past the Post, a candidate needs to simply win the most votes in order to win a seat. It doesn’t matter whether the top candidate has 99% of the vote or just 9% of the vote, just that they come out on top.
Of course, it’s highly unlikely that any candidate will win with such a small percentage in any riding. But if we break down the ridings that the two main parties are most likely to win, The Liberals are projected to have a higher proportion of seats won with under 40% of the vote than the Conservatives do, while the Conservatives are projected to have a higher proportion of seats won with over 50% than the Liberals.
This means that the Conservatives, despite being forecast to win fewer seats than the Liberals, will have more votes in excess of what they need in those winning seats than their rivals. If these excess votes were cast in more competitive ridings, then that would allow them to be more efficient with their vote.
Winning the Marginals
I’m going to define a marginal riding as a riding where two or more parties are projected to be within 10 percentage points of each other. Winning the marginals makes your vote more efficient (as there are fewer votes in excess of what you need to win), while losing the marginals makes your vote less efficient (as you get nothing from them).
I’m currently projecting 108 seats to be marginal seats, with over half of them (55) forecast to go to the Liberals, and only 33 going to the Conservatives. Meanwhile, the Conservatives will have more marginal defeats than the Liberals, but not by quite a pronounced margin (44 vs 39, counting only defeats by 10pp or less).
Winning the three-way marginal is even more lucrative, as that typically requires a smaller vote share than a two-way marginal. A few days ago it looked like the Liberals would win a majority of these three-way marginals, but now it’s looking more even between the three main parties (though the Liberals are still likely to have the most with 8, compared to 7 for the Conservatives and 6 for the NDP).
Improving Conservative Efficiency
It’ll come as little surprise that most of the Conservatives’ wasted votes are in Alberta. 9 of the 10 ridings that they won by the largest vote margin are in that province (the other is in BC), and between those ten ridings there are more than a quarter million votes projected to be wasted.
On the other hand, the 50 nearest misses for the Conservatives can all be won with just over 125,000 additional votes between them. Of these, 22 are in Ontario, 12 in Atlantic Canada, 2 in Québec, and 14 in the west and north of the country.
If the Conservatives want to improve their vote efficiency, they should focus on picking up votes in Ontario, and not be afraid of losing votes in Alberta in the process. The excess votes in two safe Alberta ridings would be more than enough to flip 20 seats in Ontario to the Conservatives, and in a tight race, this could mean the difference between winning and losing this election.
Canada’s 44th general election will be held on Monday, September 20, 2021.
