The list of MPs elected under a party banner, and then re-elected as Independents, is a short one. Jody Wilson-Raybould and Jane Philpott hope to add their names to that list in October.

History suggests the odds are stacked against them — but they still might be able to pull it off.

On Monday, Wilson-Raybould and Philpott — two former cabinet ministers who were expelled from the Liberal caucus following the fallout of the SNC-Lavalin affair — announced they would run for re-election this fall as Independent candidates.

Touting the need for more non-partisanship in Ottawa and condemning the party system that has prevailed in Canada since Confederation, the two MPs promised that they would change the way politics is done if they are sent back to Ottawa — with the help of other independent-minded MPs.

Their problem is that Independents have struggled to win seats in the House of Commons in the past.

According to a dataset compiled by Semra Sevi of the Université de Montréal, throughout Canadian history there have been 74 MPs elected under a party banner who attempted to be re-elected as Independents (including all variations of that designation). Only 24 of them — just short of one-third — were successful.

That winning rate has worsened in modern times as the party system has become more entrenched — to just 26 per cent since 1945.

That compares very poorly with the historical re-election rate for incumbents as a whole: about 75 per cent.

Since 1974, only four MPs have successfully been re-elected as independents after leaving (or being booted from) their parties: Gilles Bernier (father of People's Party Leader Maxime Bernier) in 1993, John Nunziata in 1997, Chuck Cadman in 2004 and BIll Casey in 2008.

Going by the historical odds alone, Wilson-Raybould and Philpott wouldn't be the favourites in their respective ridings.

The reasons make a difference

But the reasons behind a politician's decision to run for re-election as an Independent do make a difference.

In recent years, at both the federal and provincial levels, newly-independent incumbent candidates have retained an average of about two-fifths of their vote share when facing the electorate without their former parties behind them.

If Wilson-Raybould and Philpott meet that benchmark, they're unlikely to win. Philpott took 49 per cent of the vote in Markham–Stouffville in 2015. Wilson-Raybould took 44 per cent in Vancouver Granville. If they manage to hold only two-fifths of those votes, they'd take less than 20 per cent of ballots cast.

But Independent incumbents who left their parties for what can be described broadly as 'positive' reasons retained about two-thirds of their vote shares. Those who left for what could be called 'negative' reasons — or those who left under a cloud of scandal or criminal charges — retained a much smaller portion of their support.

Casey, who left the Conservatives after he claimed their 2007 budget broke the Atlantic Accord, was a rare example of someone who actually increased his share of the vote as an Independent candidate. (After stepping away from politics, Casey successfully made a comeback with the Liberals in 2015, but will not be re-offering in October.)

Philpott likely will have to match Casey's record to win.

Wilson-Raybould better off than Philpott as an Independent

Markham–Stouffvile is a swing riding that goes between the Liberals and Conservatives. The two parties combined for 92 per cent of the vote in 2015 — and Philpott won it by a margin of just six points.

That makes things difficult for Philpott the Independent. If she is able to retain two-thirds of her vote from 2015, that would still put her at only around 33 per cent. For her to win, she would need both the Liberal and Conservative candidates to fall below that score. With the Conservatives leading in the polls nationwide and doing at least as well in Ontario as they did in 2015, that seems unlikely.

Philpott's path to re-election requires that she retain almost all of her Liberal support while siphoning votes away from the Conservatives as well. That might be tricky for a candidate who called the Liberal platform "awesome" in her announcement on Monday.

Independent MP and former Liberal cabinet minister Jane Philpott will run as an independent candidate in the riding of Markham–Stouffville in October's federal election. (Nathan Denette/Canadian Press)

Wilson-Raybould's chances are better in Vancouver Granville, which has been a three-way race in the past. Wilson-Raybould won with 44 per cent of the vote in 2015, well ahead of the NDP's 27 per cent and the Conservatives' 26 per cent.

If Wilson-Raybould retains two-thirds of her support, she would still take about 30 per cent of the vote. That might be enough in a divided field — and would have been enough to beat the NDP and Conservatives in 2015. Considering Wilson-Raybould's profile, her chances of retaining more of her vote appear better than they would be for most past Independent candidates in the same position.

Of course, there's a reason Independents have had such a hard time winning election to the House of Commons throughout Canadian history. Independent MPs play a relatively insignificant role in Parliament — and voters know that. Voters also tend to base their voting decisions on party platforms and party leaders, rather than on the local candidate. There are institutional and financial advantages to running under a party banner that Independent candidates simply do not share.

But Wilson-Raybould and Philpott have demonstrated already that they don't believe the old rules of Canadian politics should apply to them. In October, they'll find out how far that belief can take them.

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