The push for a merger between the Liberal Party and the NDP has quickly become a major issue among the growing field of candidates to replace Jack Layton, threatening the steely discipline and tight focus that propelled the New Democrats to unprecedented standing in Ottawa.
Without Mr. Layton, the NDP establishment has been unable to put a lid on speculation about greater unity among parties that oppose the Conservative government in Parliament. The top contenders for the NDP leadership – party president Brian Topp and House Leader Thomas Mulcair – are being forced to deal with the thorny issue after maverick MP Pat Martin said he will run if no one else takes a pro-merger position.
The field of potential candidates kept growing on Tuesday as caucus members such as Robert Chisholm of Nova Scotia and Françoise Boivin of Quebec, a former Liberal MP, said they were exploring a bid.
The NDP is trying to keep its leadership race as civil as possible and focused entirely on strengthening the party so it can defeat the Conservatives in 2015. But the debate about a possible merger is emotional and stands to create divisions among the disparate factions that were held together by Mr. Layton, who died last week.
Speculation about closer collaboration has arisen because both the NDP and the Liberal Party have interim leaders, who do not have the authority to stop it. The situation leaves the parties open to tensions at a time when they would otherwise devote their energies to keeping a tight check on the newly elected Conservative majority when the House comes back on Sept. 19.
"This is a window of opportunity while both parties are in a transition stage," Mr. Martin said in an interview.
The Manitoba MP said the New Democrats can form a government by going alone, but that a formal deal with the Liberals would bring a "guaranteed majority." Mr. Martin said the "pussyfooting" had to stop, and that if no one took up the issue in the NDP, "I'll do it myself."
His comments echoed the views of Liberal MP Denis Coderre, who said on Monday that "all options" have to be studied to eliminate divisions between Canada's progressive forces.
While cool to the idea, neither Mr. Topp nor Mr. Mulcair closed the door entirely on Tuesday to discussions with the Liberals. Interim leader Nycole Turmel's office called on the party to concentrate on its role as the Official Opposition, without shutting down discussions of a merger.
"This is not something our party is focused on or talking about. Our priority right now is the upcoming fall session of Parliament and holding the Conservative government to account," NDP spokesman Karl Bélanger said.
The Liberal hierarchy is much more strongly opposed to merger talks, with interim leader Bob Rae describing the issue as "fiction" and "media speculation."
The rules for the NDP leadership race will be announced by the party's federal council on Sept. 9, including the date and the location. Speaking in Montreal, Mr. Mulcair said he won't announce his leadership intentions before then, and more likely after the House resumes.
Mr. Mulcair said he has a lot of work to do sounding out support across the country, along with the fundraising possibilities.
The last co-operation agreement between Liberals and the NDP ended in failure in 2008, Mr. Mulcair noted, and his focus would be to form an NDP government. But he left room to wiggle.
"The way to get there is to have ideas that will connect with the greatest number of Canadians possible. No matter where these progressive forces come from, we will make sure we have enough Canadians to form the next government," Mr. Mulcair said.
In an e-mail, Mr. Topp said he will follow in Mr. Layton's footsteps and continue to encourage collaboration with other parties in the House without focusing on a merger.
"New Democrats aren't interested in becoming Liberals. And as recently as [Monday] the Liberals said that a merger with the NDP isn't on their agenda. I don't think it's on ours, either," Mr. Topp said.
Still, Mr. Topp said the NDP's "open-mindedness to working with others was seen as one of Jack's best attributes by Canadians right across the country. It was a big part of our victory in May."
Mr. Topp has the potential to obtain pan-Canadian support, given that he was born in Quebec, spent years working with the NDP government in Saskatchewan and is now based in Toronto. However, a number of NDP supporters were taken aback when his name was floated as a potential candidate last week, shortly after Mr. Layton's death.
"We were somewhat surprised when it came out as quickly as it did, but that's the game," said NDP MP Ève Péclet.
There is speculation within the party that an early timeline on the leadership vote, such as next January, would favour Mr. Topp at the expense of caucus candidates such as Mr. Mulcair, who have parliamentary duties in Ottawa.
Other NDP caucus members who are considering a leadership bid include Ontario's Charlie Angus and Paul Dewar. British Columbia's Peter Julian and Megan Leslie of Nova Scotia are also reported to be thinking about running. There is also talk that Olivia Chow, a Toronto MP and Mr. Layton's long-time partner, will consider entering the race, although her lack of fluency in French could hinder her chances. The NDP has 59 of its 103 seats in Quebec.