Liberal Leader Justin Trudeau and NDP Leader Thomas Mulcair re-confirmed Tuesday, that they will not support Stephen Harper, in the event his Conservative Party wins a minority on Oct. 19.

With less than a week to go before election day, both Trudeau and Mulcair said they'll do what it takes to remove Conservative Leader Stephen Harper from power.

At a campaign event in the Toronto riding of Beaches-East York, Trudeau said he wouldn’t abstain from a crucial vote of confidence in Harper’s government , should the opportunity arise.

"For 10 years, Stephen Harper has failed to help Canadians, to grow our economy, to create jobs," he said. "I got into politics because I disagreed deeply with the vision that Stephen Harper has for this country, and there is no circumstances in which I could either support him or even stand back and allow him to be prime minister."

Trudeau was less definitive, however, when asked if he would consider working with the NDP. Mulcair has said recently that Trudeau refused to speak with him about how the two parties might work together, in the event the Conservatives win a minority.

The Liberal leader declined to give a specific answer, noting that he's been very busy campaigning and meeting with Canadians ahead of Oct. 19. He also noted that the Liberal platform is noticeably different from the NDP platform.

"I made a very different choice from Mr. Mulcair, the choice of investing now, in our communities, in our country, in our future," he said of the Liberal pledge to run "modest" deficits in the first three years of the four-year term to increase infrastructure spending and kickstart the economy.

At an NDP event in Oshawa, Mulcair said he's always been willing to do what it takes to remove Harper from office. He accused the Liberals of having "walked away" from past opportunities to unseat Harper.

"Actions speak louder than words," he said. He gave an example from 2008, when he said the NDP and the Liberals formulated a coalition agreement. "The Liberals walked away from their own signature, and we're still stuck with Stephen Harper seven years later."

The NDP leader dismissed the notion that his party is trailing in the polls, insisting that the election is still a "three-horse" race.

"I always say the same thing: you can't put a poll in a ballot box," he said in French. "I know we're in a three-way race for the first time in history."

Meanwhile, at a Conservative rally in the Toronto neighbourhood of Etobicoke, Harper reiterated his message that there are "real consequences" for Canadian families if a non-Conservative government is elected next Monday.

Employing the same props and sound effects he used on Sunday, Harper had a small business owner come up and literally count out money the Conservatives say Canadians will lose under a Liberal government.

The Conservative leader declined to comment on what may happen if his party wins a minority.

"I won't speculate on results," he said in French. He said that it's up to voters to make a choice between a Conservative government that is committed to keeping taxes low and balancing budgets, and the other parties that will run deficits and increase taxes.

Canadians used to minority governments, but coalitions? Not so much

If both the NDP and Liberals want to defeat a possible Harper minority and not head back to the polls anytime soon, they’ll have to learn to work together, according to Maxwell Cameron, director of the University of British Columbia’s Centre for the Study of Democratic Institutions.

“If it happens that those two parties (NDP and Liberals) between them have a majority of seats in the House of Commons after October 19th, there’ll be some substantial pressure on them to work together in the spirit co-operation to make sure that Parliament itself can work,” Cameron told CTV’s Power Play on Tuesday.

Cameron pointed out that of the 20 federal elections held since 1921, 11 have led to minority governments. But unlike minority governments, coalitions are not as commonplace in Canadian federal election history.

“We’ve seen coalitions of one sort or another in Ontario, British Columbia, Saskatchewan; less common at the federal level. But it’s also very common around the world. In parliamentary democracies across Western Europe for example, coalitions are formed routinely,” said Cameron.

In the case that the election results in a minority that is not defeated, Cameron said that circumstance may be healthy for Canada’s parliamentary democracy. He says that many federal minority governments have resulted in “good things,” citing the back-to-back Liberal minorities of Lester B. Pearson in the 1960s which resulted in universal health care, the Canada Pension Plan and the current Canadian flag.