What options does PM Trudeau face in Canada's leadership crisis?

Canadian Liberal Prime Minister Justin Trudeau is under increasing pressure to quit after Finance Minister Chrystia Freeland resigned over a policy clash on Monday, setting up one of the worst crises of his nine years in power.

Here are some potential ways forward for Canada:

CAN TRUDEAU BE FORCED OUT BY HIS LIBERAL PARTY?

Unlike Britain, where party leaders are chosen by the parliamentary caucus and can be removed quickly, the Liberal leader is selected by a special convention of members. There is therefore no formal party mechanism to remove Trudeau if he wants to stay. 

That said, if members of his own cabinet and a large number of legislators call for him to go, he may conclude his position is untenable. 

CAN TRUDEAU BE FORCED OUT BY PARLIAMENT?

Canadian governments must show they have the confidence of the House of Commons elected chamber. Votes on budgets and other spending are considered confidence measures and if a government loses one, it falls. In virtually all cases, an election campaign starts immediately.

Additionally, the government must allocate a few days each session to opposition parties when they can unveil motions on any matter, including non-confidence. If all parties vote against the Liberals, Trudeau will fall. If one opposition party abstains, he will stay in power.

The House of Commons closes for the winter break on Tuesday and does not return until Jan. 27. This suggests the earliest a confidence vote could be held is in late February or March since it would likely take weeks for the opposition to propose their own motion.

IS THERE ANY OTHER WAY TRUDEAU CAN BE FORCED OUT?

Ultimate constitutional power in Canada lies with Governor General Mary Simon, who is the personal representative of King Charles, the head of state. She can in theory remove Trudeau but in real life this would not happen. "The governor general won't dismiss a prime minister who still holds the confidence of the Commons," said Philippe Lagasse, a professor and constitutional expert at Ottawa's Carleton University.

HOW MIGHT TRUDEAU SURVIVE?

Trudeau's Liberals have a minority of seats in the House and therefore rely on the support of other parties on a vote-by-vote basis to govern. Until now the left-leaning New Democrats, who seek to attract the same voters as the Liberals, have helped keep Trudeau in power. Although New Democrat leader Jagmeet Singh is under pressure to topple Trudeau, polls show his party, like the Liberals, would be crushed by the official opposition Conservatives in an election. He may therefore decide keeping a struggling Trudeau in power better serves his purposes.

WHAT HAPPENS IF TRUDEAU RESIGNS?

If Trudeau resigns, the Liberals will name an interim leader to take over as prime minister while the party sets up a special leadership convention. The challenge for the party is that these conventions usually take months to arrange and an election could occur before then, leaving the Liberals in the hands of an interim prime minister not chosen by members. This has never happened in Canada. The Liberals could try to run a shorter convention than usual but this might prompt protests from candidates who felt this placed them at a disadvantage.

There is no way Freeland could quickly be named prime minister on a permanent basis, since tradition dictates that the interim leader does not run as a candidate to lead the party. If Freeland decided to contest the race, she and other serious contenders would not be considered for the role.