No opposition coalition has ever kicked a Canadian government from power. Yet here we are, with the Liberals, NDP and Bloc Quebecois threatening to do just that.

Prime Minister Stephen Harper's only option is to ask the Governor General to prorogue Parliament, essentially delaying his potential defeat until January. Otherwise, the coalition has threatened to topple the Conservatives as early as Dec. 8.

CTV.ca spoke to constitutional law expert Stephen Scott, a professor emeritus at McGill University, to find out exactly what's going on. Here are the ins and outs of a blockbuster political move that few saw coming:

What the heck happened? Is this legal?

As word of a possible coalition first broke, some readers posted comments to CTV.ca wondering whether it was anti-democratic and a "bloodless coup." Some even wrote that booting Harper in such a fashion was treasonous.

Canada's Parliament is based on Britain's Westminster system and follows the conventions of responsible government. That means the government must have the confidence of the House of Commons in order to function.

"Therefore, if the government loses the confidence of the House, or doesn't have it, the House is supposed to get a new government," Scott told CTV.ca by phone from Montreal.

The Governor General essentially has two options: dissolving Parliament and sending Canadians to the polls, or finding a new government that does have the confidence of the House. If the country has recently had an election, like in the present case, then finding an alternative coalition government is preferable.

Parliament Hill has only ever seen one real coalition, and that was back in 1917, when Sir Robert Borden managed to combine his own Unionist party with the Liberals.

Why does the Governor General make the decision? Can the prime minister fire her?

Although Governor General Michaelle Jean fills a largely ceremonial role, she is still the representative of Queen Elizabeth II. And cabinet ministers, including the prime minister, are instruments of the Monarchy.

"These are mere servants," said Scott, who used the analogy of a religious minister being subservient to the will of God.

In Pakistan, which closely followed a Westminster style of government for years after becoming a new state in 1947, one of its governors general even managed to have the Queen dismiss the prime minister.

I thought the NDP and Liberals didn't have enough seats

The Conservatives have 143 seats, just short of a majority in the 308-seat House. The Liberals have 77 and the NDP has 37, which only adds up to 114.

However, the Bloc has agreed to support the coalition for the next 18 months. No Bloc MPs will have cabinet posts, but the party's 49 seats would bring the coalition to a total of 163 votes to pass key legislation.

Scott said it doesn't matter how the coalition is formed; all that matters is whether the Governor General feels the new government would be stable.

"It can be a coalition with the support of a third party, or one party with the support of two," said Scott.

However, he said Jean should ask for the exact terms of the coalition, such as how the parties plan on supporting one another, and how long they expect the coalition to last.

In the present case, the coalition has already announced what sort of economic legislation it hopes to table, that Liberal Leader Stephane Dion will lead the government, and that it will last until June of 2011.

Meanwhile, the public can only guess at possible side deals between the parties, and what it means for Canada to have a separatist party with a hand on the reins.

What's the political fallout?

Surprisingly, it may be the Liberals who have the most to lose in the long-run. The party has always presented itself as the one true alternative to the Tories, and a party that occupies a wide swath of the political spectrum to represent the majority of Canadians.

But now, the Liberals are relying on two other parties to form a government, and the stature of those parties could grow on the political landscape.

"Once you let the nose of the camel into the tent, you might get the whole camel in the tent," said Scott. "In this context, Layton is the camel."

He said Layton may tell the Liberals he only wants a small part in the coalition, such as a few cabinet posts. But if the coalition does form a government, voters who don't normally vote NDP may get used to the idea of Layton in power.

That's bad news for the Liberals.

"The NDP are always on their heels to become the second party, and in my view, the Liberals run a serious risk of eroding their already-eroded position as a second party," said Scott.