The longest modern federal election campaign is almost over. Maybe it’s not too early to wonder who will govern, if the result is not clear.

Stephen Harper has given his answer, or part of it. “Obviously, our view is we’re going to win and we’re going to win strong,” the Conservative leader told Peter Mansbridge on Sept. 3. “But my position has always been, if we win the most seats, I will expect to form the government. And if we don’t, I won’t.” The third sentence, the shortest, was the most important.

Mansbridge pressed him. “So, even as the current government, if you’re just a couple of seats behind, you wouldn’t try to figure out a way to—”

Harper cut in. “No. No.”

Mansbridge: “You would resign.”

Harper: “Yeah. Well, I would not serve as Prime Minister.” There followed some approximations about how parliamentary government works, and Harper concluded with: “We ask people to make a choice of a government, and so I think that the party that wins the most seats should form the government.”

This was significant. As Mansbridge understood, any government remains Canada’s federal government through a campaign and afterward. No matter what the election result, any government may choose to “meet the House,” to test whether it can still command a majority of members’ support in a confidence vote. If it lost that confidence vote, the Governor General would be free to call on some other combination of MPs to form a government that could enjoy the confidence of the House.

These conventions are unfamiliar to us, because election results are usually so clear nobody bothers. In 1993, it was obvious Kim Campbell’s Progressive Conservatives no longer enjoyed the confidence of the House. There were only two PC MPs left. And neither of them was named Kim Campbell. After the 2006 election, Paul Martin still had the right to test the House with a confidence vote, but since the Conservatives won 21 more seats than his Liberals did, his government resigned on election night. This is almost always so obvious that steps in the process get skipped.

But this time it’s reasonable to assume the outcome after Oct. 19 will be less clear. Now if the Liberals or NDP win the largest number of seats, it’s reasonable to assume Harper will keep his word, resign as PM on election night, and let the other party form a government, even without a majority of seats. The Harper era would be over.

But what if it’s the Conservatives who have the largest number of seats?

Again, if Harper’s party wins a majority—at least 170 of 338 seats—the answer is obvious. There could be no effective challenge to continued Conservative government. And if they don’t? In the 2011 campaign, Harper was categorical: There could be no Conservative minority government because the Liberals and NDP would team up to deny it confidence in Parliament. Sure, there had been minority governments before. But after 2008, when Stéphane Dion and Jack Layton had tried and failed to form a coalition to replace him, their parties would certainly try again. Only a “strong, stable, national Conservative majority” would be proof against their depredations.

This year, Harper has said nothing of the sort. In 2011, after seven years of minority governments and their uncertainty, voters were tired. For many, the prospect of a Conservative majority was reassuring. Now it’s largely reversed: A lot of voters are tired of the Harper majority and are willing to put up with uncertainty if it represents change. That’s why both Justin Trudeau and Tom Mulcair have insisted they would not help a Conservative minority govern.

But I can easily imagine a stable Conservative minority.

Related: This or that? Find out where you stand this election with the Maclean’s Policy Face-Off Machine

Look, if the result is close—if the Conservatives win 114, the Liberals 112 and the NDP 110—I think Harper would resign soon after an election. The Conservatives would have lost 45 seats and a chunk of the popular vote. Another party’s claim to power would be persuasive. Something like this happened in Ontario in 1985, when the incumbent Progressive Conservatives won only four seats more than the Liberals. A confidence pact between Liberals and New Democrats put an end to PC government.

But what if it’s less close? Remember that 170 is a majority. What if Harper won 169 seats, the others, fewer than 90 each? A lot of voters would say, “Let the Conservatives govern.” And if that’s true at 169 Conservatives, it would be nearly as true at 159, or 149. As long as the gap between first- and second-place party caucuses is significant, some large component of public opinion would say the party with the most seats should govern.

When I talk like this, I always hear from someone who says public opinion doesn’t matter, and only the arithmetic in the Commons determines who gets to govern. To introduce notions like perceived fairness is to betray a misunderstanding of parliamentary democracy. I think that’s backward. Arithmetic in the Commons is the sum of the decisions of the fallible humans in it. They got there by winning elections. They’ll hope to win again. They can’t have voters too angry at them.

If the outcome on Oct. 19 isn’t clear, each MP one way or another will count. So will the claims they make, in person and on TV and Twitter, to power. Brinksmanship is much likelier than calm. Any conceivable outcome will upset a lot of people. That’s politics.