We all know that it’s seats that matter, not the popular vote.

How does popular vote translate to seats, and what is the threshold for winning a minority or a majority in federal politics?

In the past 60 years, the magic number has been a minimum of 38.5% for a majority and a minimum of 35.9% for a plurality of the seats, which historically leads to a minority government.  The highest popular vote that did not translate into a majority was 41.5%, therefore, the modern-day range has been 38.5% to qualify for a majority and over 41.5% to be free and clear of a minority.

In 2015, Justin Trudeau’s Liberals finished above the 38.5% ‘minimum’ for majority governments, earning 39.5% of the popular vote.

Chart: Popular vote of party that formed government with plurality of seats

In fact, only Lester Pearson’s Liberals were unlucky enough to be above the 38.5% mark and not win a majority – in consecutive elections too.  John Diefenbaker’s Progressive Conservatives were on the 38.5% line in 1957 and missed out on a majority that time. In 1958, he took care of business with a majority of seats and votes.

Jean Chrétien in 1997 had the lowest popular vote at 38.5% in past 50 years to win a majority.  Here is a list of the majorities and popular vote since 1957:

Joe Clark’s Progressive Conservatives had the lowest popular vote to win a plurality of seats (35.9%).  Not only that, he lost the popular vote by five points to Pierre Trudeau’s Liberals, but he still won more seats.  Here are the minority governments:

Sure, a majority could be earned nationally with less than 38.5% of the vote.  It’s happened provincially.  François Legault won a majority with 37.4% of the vote in Québec’s 2018 election.  The Bob Rae government scored 57% of the seats with 37.6% of the vote in 1990.

The 2019 election and after

So far in the 2019 election, the public polls indicate that the two contending parties – Liberals and Conservatives – are falling below the 38.5% threshold.

If they continue to hover in the 35% range, the likelihood of Jagmeet Singh’s NDP, Yves-François Blanchet’s Bloc Québécois, and/or Elizabeth May’s Greens holding the balance of power increases.  It could even be an independent if the margin between minority and majority is razor thin.

Canada was governed by minority governments from 2004 to 2011.  It was Jack Layton’s NDP that pulled the plug on Paul Martin’s Liberal government.  Stephen Harper’s Conservatives governed with a minority for five years thanks to the NDP.

This time, winning a plurality of seats is no ticket to the Prime Minister’s Office.  Jagmeet Singh has said as much.  Elizabeth May says she may not decide to prop up anyone.  Andrew Scheer may find it harder to pull together confidence than Stephen Harper – the Bloc Quebecois may be his only hope, which would be ironic when considering the aftermath of the 2008 election.

Crossing that line of 38.5%, or wherever it exactly lies, will ensure the government is decided on election day.  Falling short means that winning the confidence of 338 Members of Parliament will be the election that takes place soon after, and that will be decided in the backrooms.