With the possibility of a majority Parti Québécois government for the first time in almost a decade, federal parties are closely watching the Quebec election. CBC News has learned that earlier this week, when the prime minister and the leader of the Official Opposition met to discuss Ukraine, the prime minister also asked Tom Mulcair for his take on the election.

Mulcair is a longtime Quebec politician with direct knowledge of the players, so Stephen Harper took the opportunity to ask the NDP leader about the possible outcome of the April 7 vote and the chance of a sovereignty referendum.

When asked about the meeting, Harper's and Mulcair's offices would only say the official topic of conversation was Ukraine and the meeting was private.

Sources also told CBC News the prime minister spoke to Liberal leader Justin Trudeau at length and the Quebec election was raised. Liberals have a history of fighting for national unity.

There are also reports the Harper reached out to premiers across the country. The Prime Minister's Office would not confirm any private meetings.

In all his time as prime minister, Harper has never faced a majority PQ government or the very real threat of a referendum.

Harper has a good relationship with Marois and respects her, but things might get more difficult for the prime minister if Marois's party wins a strong majority, warns André Bachand, who was Harper’s senior Quebec adviser up until this fall. 

"I think the relationship will be a little bit harder between the premier’s office in Quebec and the PM's office in Ottawa if there is a majority government," said Bachand.

Conservatives have only 5 Quebec MPs

Undoubtedly, it will also be harder given Harper only has five Quebec MPs and the Conservative Party itself is not particularly popular in the province right now. 

Mulcair, on the other hand, has decades of experience as a Quebec politician, was a cabinet minister for Jean Charest and was in the province during the last two referendums in 1980 and 1995.

He knows these players.

"I've known Pauline Marois for more than 30 years," Mulcair said, "She's a redoubtable political figure, and she's showing that."

Mulcair is careful with his language because he has much at stake during this election, too.

He shares some voters with Marois, those with progressive and soft-nationalist leanings, and he can't risk upsetting them.

Marois might not risk it

One of Harper's former Quebec ministers and senators, Michael Fortier, is warning all parties to be careful.

"The horse we all have in the race is that there is not a third referendum," said Fortier.

'I think her generation, they suffered two losses, and they know a third defeat would likely be the end of the story,'- Michael Fortier, former Quebec senator, minister

Fortier, now a vice-chairman at RBC Capital Markets in Quebec, says there is something else to keep in mind: Marois likes her job and won't necessarily risk another referendum.

"I think her generation, they suffered two losses, and they know a third defeat would likely be the end of the story," he said. "They don't want this to be their legacy. And I don't think there will be a referendum unless the PQ believe they can win it."

Bachand agrees with that take, but he also says there is something else the prime minister will have to keep an eye on in the coming weeks.

"The thing we need to watch is not the reaction of governments, but the reaction of people elsewhere in Canada who might say quite clearly to the prime minister, 'Stop talking [to] those people in Quebec because they want to destroy Canada."

All three major federal parties may well find themselves knocked off their own agendas and facing a common cause in Quebec in the weeks and months ahead.