Q: If the Opposition parties in the House of Commons - the Liberals, NDP and Bloc - pass a motion stating they've lost confidence in the government lead by Stephen Harper's Conservatives, how is an election triggered?
A: The prime minister visits the governor-general - currently David Johnston - to say that Parliament has lost confidence in his government. Only six Canadian governments have lost a confidence vote: Arthur Meighen's in 1926, John Diefenbaker's in 1963, Pierre Trudeau's in 1974, Joe Clark's in 1979, Paul Martin's in 2005 and now Stephen Harper's in 2011. Only a minority government usually loses a confidence vote, because it doesn't control a majority of seats.
The prime minister then requests the governor-general dissolve Parliament, so voters can elect a new Parliament.
Q: Why does the prime minister have to go to the governor-general?
A: As the representative of the Queen and the head of state, only the governor-general can call a new election (but does so only when requested by the prime minister).
Q: Could the governor-general say no?
A: Technically, he can say no. But in practice, that almost never happens.
Constitutional scholars say it would be acceptable for a governor-general to refuse a request to dissolve Parliament only if:
a) An election had been held very recently, and there had been no time or issues likely to change the mind of the electorate. In other words, a prime minister couldn't call a new election if he or she disliked the results of the election just held.
b) An alternative government could be formed by other parties in the House.
This has happened only once in Canadian history: In 1926, shortly after an election had returned a Liberal government propped up by the Progressives, the Liberal Prime Minister lost the confidence of the House and requested a new election. The Governor-General, Lord Byng, refused and allowed the Conservatives to form a minority government. That Conservative government was later defeated, an election was then called and the Liberals won a majority.
In 2008, Mr. Harper's minority government faced the prospect of losing a no-confidence vote, as the Liberals, NDP and Bloc prepared to form a coalition government to replace the Conservatives without triggering an election. However, the plan was short-circuited when Parliament was prorogued and enthusiasm for the coalition fizzled.
Download the MP3 of an interview with Peter Russell on the governor-general's powers.
Sources: Peter Russell, professor emeritus at the University of Toronto; Ned Franks, professor emeritus at Queen's University; The Canadian Encyclopaedia