In a textbook case of vote splitting, Conservative candidate Joan Crockatt won the federal byelection in Calgary Centre Monday night with 36.9 per cent of the vote, 21 points below the 57.7 per cent victory of the former Conservative MP who resigned the seat.

She will join a dozen or so Conservative MPs who won their ridings by fewer than 1,200 votes, but what stands out about this particular squeaker is that it happened in Calgary, in a seat once considered one of the safest in the Conservative heartland.

But Crockatt's nail-biter win likely won't dent her career in Ottawa. In a first-past-the-post system, coming first is all that matters.

"We tend to forget [margins] very, very quickly" said Harold Jansen of the University of Lethbridge. "It will be a story for a day or two."

But the closely fought byelection, as well as the Green Party's close second in Monday's Victoria byelection, is perhaps part of a trend that shows the so-called progressive vote is now split three ways, rather than two, adding in the Greens as the third prong.

In Calgary, Liberal Harvey Locke came a close second at 32.7 per cent, followed by the Greens' Chris Turner, who took a surprising 25.6 per cent of the vote, and the NDP's Dan Meades trailing badly at 3.8 per cent.

The Green candidate's showing in Calgary means that "the Greens are a serious competitor with the NDP for the left-of-centre vote," said Jansen.

Blogger David Climenhaga of albertadiary.ca, who considers himself a progressive voter and who once worked closely with Crockatt, thinks the Green Party is now in the position of being the spoiler.

"If I were a Tory, I'd want to donate to the Greens right away."

'The Green Party is not a small party'

Federal Green Party Leader Elizabeth May said at a press conference Tuesday, "I'm encouraged that I think we've proven that the Green Party is not a small party, not a blip, or that my seat is the only one we'll ever win."

She complained that when the byelections were first announced, most of the media didn't even mention who the Green candidate was.

May also said, somewhat surprisingly, that the calibre of the Green candidates in Calgary Centre and Victoria was such that they may not have considered even running for her party as recently as 2011. The Green tide is rising, she seemed to be saying. What she didn't say is that she could now potentially be a power broker in any discussions about electoral co-operation between the three mainstream non-Conservative parties.

Jansen thinks that the Greens' buoyancy could have been due, partially, to Crockatt's "lack of effort" in the campaign, particularly her no-shows for a lot of the debates.

Duane Bratt, of Mount Royal University in Calgary, says it also helped that the Greens' Turner had many people working for him who had also worked on Calgary Mayor Naheed Nenshi's winning campaign.

And despite Liberal MP and leadership candidate Justin Trudeau's anti-Alberta musings, it probably didn't hurt that he campaigned side-by-side with Harvey Locke at several events, said Climenhaga.

A test for party cooperation

Whatever the reasons, Calgary Centre neatly replicated the popular vote across the country in the last federal election.

"I think it will become a real test on party co-operation," said Bratt of the vote split Monday night, but noted the byelection was not the time or place to come together. "How could they co-operate at a byelection in Calgary when they haven't even talked at a national level? But this may drive the national level a bit more."

Jansen thinks that what happens in the next federal election, almost three years away, has more potential to be the catalyst that will force a merger or co-operation agreement. "That discussion is going to reignite [now], but I'm not convinced that will spur anyone to much action on the basis of a byelection."

What the results of the Calgary Centre byelection might do is simply further frustrate the 60 per cent of voters who did not vote Conservative in the last election. This could be a cue for Liberal Party leadership candidates, who might recall that the NDP's Nathan Cullen attracted a lot of support due to his co-operation policy when he ran for his party's leadership.

Liberal MP Joyce Murray, who declared her candidacy for the Liberal leadership Tuesday, has suggested run-off nominations for progressive candidates in close ridings.

Trudeau has said he supports the concept of preferential voting, in which voters mark their second (and third or fourth) choices on their ballots.