The Supreme Court of Canada will begin hearing the case of the overturned election result in Etobicoke Centre on Tuesday and if it upholds the ruling of the Ontario Superior Court, voters in the riding will be headed to the polls in a byelection before the year is up.

If the 2011 result in the riding is any indication, it could be a close one.

When the ballots were counted on May 2 of last year, Conservative candidate Ted Opitz came out on top with 21,644 votes to the incumbent Liberal Borys Wrzesnewskyj’s 21,618 votes. So close was the result that two decimal points are needed to express the outcome: the Conservatives took 41.21 per cent of the vote to the Liberals’ 41.16 per cent.

The riding is a patchwork of Liberal and Conservative pockets of support, with a few NDP-voting neighbourhoods added to the mix for good measure.

But the federal Conservatives have slipped in Ontario by as many as eight points. At the same time, the Liberals have held steady since the May 2011 election, suggesting Etobicoke Centre should swing to them. The NDP, however, is up seven points in the province and could cause a problem for Wrzesnewskyj. How much of that Liberal vote will the NDP be able to attract?

Unlike during the last election, when only the possibility of the NDP in opposition could be imagined, the New Democrats have become a serious alternative to the Harper Conservatives.

The Liberals are also now cast in a different shadow. Whereas they are presently third party in the House of Commons, leaderless and faced with a questionable future, at the time of last year’s vote the scope of the disaster that was about to befall them was unknown. Now that the political landscape has shifted so dramatically, for which opposition party will anti-Harper voters cast their ballot?

It will be a difficult balancing act for the Liberals. Not only will they need to prevent voters from switching over to the New Democrats, they will need to convince them to overturn the results and opt for an opposition MP over one that sits in the government. Wrzesnewskyj is at least a known quantity, having represented the riding from 2004 to 2011, but Opitz has been the MP for Etobicoke Centre for over a year now.

If the Supreme Court decides that a byelection should be held, it will be a tight race. Both the Conservatives and Liberals can be expected to pour the maximum amount of resources into the fight. But in order to minimize the effects of a loss, the Conservatives will have the option to hold byelections in two other safe ridings on the same date.

In Calgary Centre, where former MP Lee Richardson accepted a job with Alison Redford’s Alberta government, the Conservatives are certain to come out ahead. They won by 19,770 votes in 2011, with 57.7 per cent of ballots cast. Slightly less certain is the outcome of the upcoming Durham byelection due to the end of Bev Oda's controversial tenure. But with a 19,460-vote margin of victory and a 54.5 per cent vote share of the vote last year, Durham is still a likely hold for the Conservatives.

Even with byelections being held in the two other ridings, Etobicoke Centre will be the focus of attention. There is no question that it would be a closely fought contest – what remains to be seen is whether the Supreme Court believes it should take place.

Éric Grenier taps The Pulse of federal and regional politics for Huffington Post Canada readers on most Tuesdays and Fridays. Grenier is the author of ThreeHundredEight.com, covering Canadian politics, polls, and electoral projections.

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  • It has been just over a year since the last federal election, one that has become known almost as much for allegations of electoral fraud in Guelph, Ont., as for the way it redrew the House of Commons.<br><br> <a href="http://www.huffingtonpost.ca/news/robocalls-scandal" target="_hplink">Investigators are now looking into calls wrongly claiming to be from Elections Canada that redirected voters to a polling station they couldn't use</a>. It's illegal both to interfere with a person's right to vote and to impersonate Elections Canada.<br><br> A year later, here's what we do know, according to court documents and information provided in interviews:<br><br> <strong><em>With files from CBC.</em></strong><br><br> (CP)

  • 1. Probe Started Early

    Elections Canada investigator Al Mathews started looking into complaints in Guelph on May 5, 2011, three days after the election that saw reports of illicit phone calls. The winning candidate in the riding, Liberal <a href="http://www.huffingtonpost.ca/2012/03/10/robocalls-by-liberals-guelph_n_1336895.html" target="_hplink">Frank Valeriote, compiled a list of almost 80 names</a> of people complaining about the calls. News of the investigation didn't break until Feb. 22, 2012. (Thinkstock)

  • 2. RackNine

    All political parties use automated robocalls and live calls to identify voter support and contact people during a campaign. <a href="http://www.huffingtonpost.ca/2012/02/23/racknine-robocalls-elections-canada_n_1296383.html?ref=robocalls-scandal" target="_hplink">The campaign of Guelph Conservative candidate Marty Burke used RackNine</a>, a company that offers voice broadcasting services, to make legitimate robocalls to campaign supporters. The person who made the fraudulent robocalls also used RackNine. (Alamy)

  • 3. Pierre Poutine

    The <a href="http://www.huffingtonpost.ca/2012/02/28/robocalls-scandal-pierre-poutine_n_1307730.html?ref=robocalls-scandal" target="_hplink">person who made the calls used a disposable, or burner, cellphone, registered to a "Pierre Poutine."</a> The RackNine charges were paid via PayPal using prepaid credit cards, purchased at two Shoppers Drug Mart stores in Guelph. Shoppers Drug Mart doesn't keep its security camera videos long enough to see who bought the cards more than a year ago. (Alamy)

  • 4. IP Traced

    <a href="http://www.huffingtonpost.ca/2012/05/04/andrew-prescott-pierre-poutine-robocalls-conservative_n_1478809.html?ref=robocalls-scandal" target="_hplink">Elections Canada traced the IP address used to access RackNine</a> on election day and send the fraudulent message. Mathews got a court order for Rogers, the company that provided the internet service to that IP address, to provide the customer information that matches that address, on March 20, 2012. (Alamy)

  • 5. Andrew Prescott Linked To Poutine IP

    <a href="http://www.huffingtonpost.ca/2012/05/04/andrew-prescott-pierre-poutine-robocalls-conservative_n_1478809.html?ref=robocalls-scandal" target="_hplink">Pierre Poutine and Burke campaign worker Andrew Prescott (pictured here with Tony Clement) accessed their RackNine accounts using the same IP address</a>. On election day, they accessed their RackNine accounts from the same IP address within four minutes of each other, Mathews says in documents filed in court.

  • 6. But Accounts Don't Match

    A court document lists the billing account numbers for the customer information provided by Rogers to Mathews. <a href="http://www.cbc.ca/news/politics/story/2012/05/11/pol-robocalls-guelph-rogers-account-numbers.html" target="_hplink">Those accounts don't match</a> the number found on the Burke campaign's Rogers invoices submitted to Elections Canada, suggesting RackNine wasn't accessed through a computer in the Burke campaign office.

  • 7. Misleading Calls Discussed?

    Two Conservative staffers, accompanied by the party's lawyer, told Mathews they overheard <a href="http://www.huffingtonpost.ca/2012/05/04/michael-sona-robocalls-pierre-poutine-guelph_n_1479400.html?ref=robocalls-scandal" target="_hplink">Michael Sona (pictured here with Stephen Harper), another Burke campaign worker, talking about "making a misleading poll moving call."</a> Sona, who stepped down from a job in the office of Conservative MP Eve Adams when the story broke, has previously said he had nothing to do with the misleading calls.

  • 8. Poutine Used Tory Database?

    Arthur Hamilton, the Conservative Party's lawyer, told Mathews the list of phone numbers uploaded to RackNine by Pierre Poutine appeared to be a list of identified non-Conservative supporters, with data on it that was updated in <a href="http://www.huffingtonpost.ca/2012/05/17/robocalls-scandal-privacy-information_n_1525197.html?ref=robocalls-scandal" target="_hplink">CIMS, the party's database</a>, days before the election. The CBC's Terry Milewski had reported a similar pattern after sifting through complaints in 31 ridings.

  • 9. Deluge Of Complaints

    <a href="http://www.huffingtonpost.ca/2012/03/29/marc-mayrand-testimony-robocalls_n_1387176.html?ref=robocalls-scandal" target="_hplink">News coverage led to 40,000 people contacting Elections Canada one way or another</a> -- whether to report a misdirecting call or by signing an online petition to express concern that it had happened -- chief electoral officer Marc Mayrand told a parliamentary committee in April. There are now specific allegations in almost 200 ridings by 800 people.