How vote-splitting helped — and hurt — the federal parties

Vote-splitting is at the heart of many heated election season discussions of strategic voting. It's often cited by Liberals late in election campaigns as a reason for progressive voters to rally around their party. Vote NDP or Bloc or Green, the argument goes, and you may elect a Conservative.

Conservatives gained in Ontario while Liberals benefited in Quebec

Liberal Leader Justin Trudeau, Conservative Leader Andrew Scheer, NDP Leader Jagmeet Singh, Bloc Québécois Leader Yves-François Blanchet and Green Party Leader Elizabeth May. Images provided by The Canadian Press. (Images provided by the Canadian Press)

Vote-splitting is at the heart of many heated election season discussions of strategic voting.

It's most often cited by Liberals late in campaigns as a reason for progressive voters to rally around their party. Vote NDP or Bloc or Green, the argument goes, and you may end up electing a Conservative.

Centre-left vote-splitting may well have helped the Conservatives this election in key battleground regions such as Ontario and suburban Vancouver.

But the Conservatives were not the only party to benefit. Vote-splitting helped the Liberals in Quebec and the Maritimes and the NDP in non-GTA Ontario and B.C.

CBC News looked at ridings where the combined vote total of the second- and third-place finishers exceeded that of the winner. We then eliminated ridings where the Conservatives and NDP finished second and third, as crossover between those two parties isn't likely.

That left 87 ridings where vote-splitting could have affected the result.

Here's a look at how it played out across the country.

Where Conservatives benefited

Liberal-NDP vote-splitting likely helped the Conservatives in 32 races, mostly in Ontario and B.C. They included some of their most hotly contested ridings in suburban Toronto and Vancouver. Some, such as Aurora-Oak Ridges-Richmond Hill and South Surrey-White Rock, were ridings the Conservatives managed to flip from red to blue.

And Liberal-Bloc vote-splitting likely helped Conservatives in a handful of Quebec ridings. The party also benefited from a Bloc-PPC split in Maxime Bernier's former riding of Beauce.

Where Liberals benefited

The Liberals were most often able to capitalize on Conservative-Bloc splitting in Quebec. In a handful of races in Ontario and the Maritimes, splits between Conservatives and the Greens may also have helped Liberal candidates win.

Where the NDP benefited

The NDP was buoyed by several three-way splits between Conservatives, Liberals and Greens on Vancouver Island, most notably in the Victoria area.

It also benefited from splitting on the centre-right between the Liberals and Conservatives in the Winnipeg area and in several Ontario ridings outside the GTA.

Where the Bloc benefited

The Bloc capitalized on federalist vote-splitting in 13 ridings.

In most cases, it was Liberals and Conservatives splitting the vote, with a few Liberal-NDP exceptions.

But in battleground Trois-Rivières, a three-way split between the Liberals, Conservatives and NDP may have helped elect the Bloc candidate.

Liberal-Conservative vote-splitting also helped Green Jenica Atwin to a narrow win in Fredericton, and helped put independent Jody Wilson-Raybould over the top in Vancouver-Granville.


Tara Carman

Senior Reporter, Data Journalist

Tara Carman is a senior reporter and data journalist with CBC’s national investigative unit. She has been a journalist in Vancouver since 2007 and previously worked in Victoria, Ottawa and Geneva. You can reach her at tara.carman@cbc.ca or on Twitter @tarajcarman.

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