Minority outcome could produce political and constitutional squabbling for months
Governor General could play a key role in deciding who forms future government
It could all come down to a mix of hard and fast rules, procedural convention and intense political manoeuvring.
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And with no party in clear striking distance of winning a majority government, there's much speculation about the scenarios that could ultimately determine the next prime minister and the party — or parties — to form government.
Canadians could be in for a wild constitutional ride in the weeks and months ahead if no party wins 170 seats — the magic number for a majority government.
Here's a snapshot of what to expect:
What if it's a minority?
After an election, the governing party can continue as a "caretaker" until the prime minister resigns or is defeated in the House. Traditionally, the leader of the party that scores the most seats takes the prime minister's title, making the case to the Governor General that he can form government and command confidence of the House.
The prime minister and his governing party can try to win that confidence on a case-by-case basis, through an arrangement with fixed conditions, or by forming a formal coalition.
Flexible or fixed time frame?
While there is no set time frame for recalling Parliament and presenting a speech from the throne (the only rule is that MPs must convene at least once in a year), the expectation is that it would happen fairly quickly to ensure national stability.
How to keep the confidence?
A minority government could topple at any time if it loses the confidence of the House. The first test would be the speech from the throne, and subsequent confidence votes would relate to budget and money bills and other issues deemed a confidence matter.
What happens when confidence lost?
Once a minority government loses a confidence vote, the Governor General must decide whether there should be another election, or whether another party or coalition deserves a crack at forming a government that would have the confidence of the House.
Philippe Lagassé, associate professor of public and international affairs at the University of Ottawa, said timing is a factor. In a CBC live blog chat, he said past convention suggests that while the Governor General has full discretion, he or she is less likely to go the dissolution route if the last election was less than six months earlier.
Do coalitions breed certainty?
Coalitions between parties can be struck in different ways, and for open or fixed time frames. A more formal agreement could help convince the Governor General there's more certainty, but Lagassé said it raises other challenges.
"The difficulty with a formal coalition lies in having to distribute cabinet positions and agree to a common set of policies," he said.
What's the GG's role?
The Governor General has discretion and power in potential constitutional crises. Important decisions on dissolving Parliament or allowing a party or coalition to govern are sometimes made after consultation with the political leaders and constitutional experts.
How unusual is a minority?
Actually, not that rare. Since 1921, Canada has held 29 elections and 13 of them have yielded minority governments. Minority governments and coalitions can be turbulent and are typically shorter-lived than majority governments, with an average duration of one year, seven months and 27 days.
For better or for worse?
Some scholars say minority governments can better reflect the public will and produce good public policy.
"It would force the parties to work co-operatively, it would be more representative, because different party platforms would have to be reconciled, so a wider spectrum of voters interests would be represented in the platforms that would eventually be made into policy," University of Toronto constitutional law professor Yasmin Dawood told CBC News Network's Power & Politics.
"And it would reduce the stranglehold of the [Prime Minister's Office] on political power in Canada," she added.
In his paper "Trust and Co-operation: Post-Election Co-operation in Parliament," political science professor Max Cameron argues that while minority governments are usually brief, they can be productive. He points to Liberal governments under Lester B. Pearson that led to policies on public health care, the Canada Pension Plan, bilingualism and the Canadian flag.
What happens if there's a tie?
So what happens if two parties win an equal number of seats? Lagassé said three things could happen.
"The incumbent PM would still be PM and could test confidence, probably after trying to see if a third party would support [him]. Alternatively, the incumbent PM could resign if she or he knows that the tied party has the support of a third party. Thirdly, the party leaders could work it out amongst themselves after the election."
2nd place, but still PM?
There are other unlikely but possible scenarios.
It's possible, for example, that an incumbent prime minister could finish in second place in terms of seat count, but still remain PM. Lagassé said an incumbent prime minister has the right to meet the House first to test confidence even if he has fewer seats, but Stephen Harper has suggested he wouldn't do so.
"All three leaders have seemingly indicated that they believe whichever party has the most seats should be given a first chance at testing confidence," he said.
In 1925, William Lyon Mackenzie King's Liberal Party remained in office even though it won fewer seats than the Conservatives.