Unlike its rivals in Ottawa, the NDP is refusing to take a stand in favour of federalist candidates in the April 7 Quebec election that will determine the fate of the Marois government.
The NDP has a strong following in Quebec's nationalist electorate, including supporters of sovereigntist parties such as the Parti Québécois and Québec Solidaire, and it is refusing to come out in favour of the province's more right-wing federalist formations.
"We didn't get involved in the provincial campaign last time around. We won't be getting involved this time," Mr. Mulcair told reporters this week.
Mr. Mulcair, a former Liberal MNA in Quebec City, even refused to state whether he plans to vote for his old political formation this time around.
By contrast, Liberal Leader Justin Trudeau has said that he would vote for the Quebec Liberals if he still lived in the province. The Conservative Party added that a majority of its supporters in the province support the Quebec Liberals or the Coalition Avenir Québec, two opposition parties that are against holding another referendum on Quebec sovereignty.
"What is certain is that [Conservatives in Quebec] believe in a strong Quebec in a united Canada," said Carl Vallée, a spokesman in the Prime Minister's Office.
The PQ is hoping to grow from a minority to a majority government on election day. If her party succeeds, PQ Leader Pauline Marois has promised to launch consultations on a white paper on the future of Quebec, which could lead to another divisive battle on the country's future.
The results of the provincial election will likely force the federal parties to adjust their positions on the Quebec file. The matter is expected to be a key issue in the 2015 federal election, especially if there are constitutional flare-ups after a PQ victory.
"There will be direct consequences [for the federal parties] the day after the election," said pollster Jean-Marc Léger in an interview. "Each party will have to position itself based on whether it is a minority or a majority government, especially if it's a PQ government."
Mr. Léger said that Mr. Trudeau is the leader that could most benefit in Quebec from a PQ victory, predicting the province's federalist voters would coalesce around his leadership. Mr. Léger said Quebeckers are used to having "belt-and-suspenders strategy" – voting for a clearly federalist government in Ottawa when there is a PQ majority in Quebec City.
"Mr. Trudeau will have a much easier time getting the support of federalists in Quebec than his rivals," the pollster said.
Still, Liberal officials point out the Liberal Party of Canada and the Quebec Liberal Party are "more like cousins than brothers." No one is expecting Mr. Trudeau to campaign next to Quebec Liberal Leader Philippe Couillard, as the federal leader did in past ballots in Ontario and Nova Scotia.
The NDP's position in the provincial election stands to cement the perception that it is closer to Quebec's nationalist electorate than its federal rivals. The NDP officially supports a simple majority of 50-per-cent-plus-one to trigger negotiations on Quebec secession, a stance that prompts constant attacks from the Liberal Party and the Conservative Party as being too accommodating toward sovereigntists.
"The [NDP] support is like a rainbow coalition, there were a lot of sovereigntists who supported the party [in the 2011 election]," Mr. Léger said.
Still, Mr. Mulcair likes to point out that he was a front-line player on the federalist side in the 1980 and 1995 referendums on Quebec sovereignty, and that no one can question his attachment to Canada.
"You don't have to have been following politics very long to know that Madame Marois' ultimate goal is not something I share," he said.
The Conservatives are planning on staying on the sidelines in the election. Still, the Conservatives said they will respond to any false attacks against the Canadian federation or the federal government.
"As is the case with any provincial campaign across the country, we have no intention of intervening," said Mr. Vallée.
Daniel Leblanc is a parliamentary reporter in Ottawa.