OTTAWA — So it’s a majority or bust for Stephen Harper.

On Wednesday, NDP Leader Thomas Mulcair did what Liberal Leader Justin Trudeau did on Tuesday to say there was no-way, no-how a re-elected Conservative minority was going to get a chance to govern.

“There isn't a snowball's chance in hell,” Mulcair told reporters in Montreal when he was asked if his party would prop up a Harper minority. “There's no likelihood that the NDP would ever under any circumstance be able to support Mr. Harper, his divisive politics [and] his backward economics.”

Trudeau was equally unequivocal the day before, also in Montreal.

“I have spent my entire political career fighting against Mr. Harper’s narrow and meaner vision of what Canada can be and what the government should do,” Trudeau said. “There are no circumstances in which I would support Stephen Harper to continue being prime minister.”

That’s a big change from Mulcair’s predecessor Jack Layton or Trudeau’s precursors, Michael Ignatieff and Stephane Dion. Each either found ways to extract something for their supporters in exchange for keeping earlier Harper minorities afloat or they found ways to register their opposition without bringing down the government. And, generally, they preferred to see what Harper was offering before rejecting it.

Not so with Mssrs. Mulcair and Trudeau. Doesn’t matter what Harper might put on the table. They’ll vote him down.

Their first opportunity will likely come in late November on a confidence vote over the Speech from the Throne, the speech that sets out the broad legislative agenda and objectives of any government.

Now, if a government loses a confidence vote mere weeks after a general election, it would be up to Governor General David Johnston to force a new election or simply let someone else have a crack at winning “the confidence of the House.”

Johnston is the right G-G for this conundrum as he is widely regarded as a constitutional expert in his own right.

But if Johnston calls on Mulcair or Trudeau to try to form a government, how would either man do it? Would it be through a formal coalition where, perhaps, one was the other’s deputy prime minister? Would it be an agreement not to bring down this new government for a certain period of time? What would the terms be?

Mulcair’s and Trudeau’s declarations this week have turned these questions away from the realm of the hypothetical and into the realm of the real. And yet, voters who seek enlightenment on these issues get only obfuscation from both New Democrats and Liberals.

Now: Is a Harper minority a likely possibility? Yes. After looking at various regional polls and after discussions with partisans working for all sides, I calculate that Harper’s Tories would today win about 124 seats in our newly enlarged 338-seat House of Commons. That’s nowhere close to the 170 seats needed for a majority.

But now, Mulcair and Trudeau, in lockstep, say that unless Harper gets 170 seats, they’ll depose him.

This, in previous elections, is just what the Conservative campaign war room wants. They love the whole us-against-the-world fight, believing it motivates their volunteers, donors, and voters. And it’s worked before for them.

By design or accident, Mulcair and Trudeau have just thrown down the glove. And the stakes in this election just got a little higher.