​There is still, in the way its members refer to each other as "brother" and "sister," something rather quaint about the New Democratic Party. Suffice it to say there is no such familial formality at conventions of the Liberal party of Canada.

One possible reading of the events in Edmonton on Sunday might be that the decisive dispatching of Tom Mulcair marked the moment the NDP became something more like the Liberal party: a demanding political organization that does not tolerate unsuccessful leaders.

In the moment, even those New Democrats who did the deed seemed surprised at what they had done.

But it also seems possible that if Mulcair had somehow been a more inspirational figure he might have been able to stay on, at least for a little while longer.

Tom Mulcair, for now, heads a party that has rejected his leadership and is looking for a new direction. (The Canadian Press / Jason Franson)

Which is perhaps to say that, even after the breakthrough of 2011 and the possibility of 2015, the NDP's definition of success might still be particular. As outgoing party president Rebecca Blaikie said in an interview this weekend, "we've never been in this game just to win. We want to win, but we're not here just to win."

At the national level, that remains a needle unthreaded and a bargain not fully tested.

Of course, Liberals and Conservatives might insist they are also so motivated. But as an insurgent party that has never formed government, the federal NDP is perhaps freer to consider its purpose and the heavy questions of principle and power.

Notley vs. The Leap

That consideration in Edmonton was defined by two big ideas: An NDP government in Alberta and the Leap Manifesto.

The latter is an aggressively ambitious mission statement that imagines we might reimagine the national economy, a document that was tabled last summer and then seems to have been rushed into the inspiration vacuum created by the NDP's disappointing result last fall.

If not for its authors' insistence that "there is no longer an excuse for building new infrastructure projects that lock us into increased extraction decades into the future," the manifesto might have merely existed as a dreamy point of debate to be chided by spectators from the cheap seats.

(To wit: the anti-pipeline sentiment that "the new iron law of energy development must be [that] if you wouldn't want it in your backyard, then it doesn't belong in anyone's backyard" could just as easily be applied to windmills. Or, to choose another topic, supervised-injection sites for drug users.)

But in declaring as much, the Leapers are positioned directly opposite an NDP government in Alberta that believes building a pipeline to tidewater is an important part of its plan to do the sorts of progressive things New Democrats would like to see done. (A conflict perhaps inflamed by Mulcair's own comments.)

NDP delegate Hans Modlich casts his vote on the Leap Manifesto during the 2016 NDP Federal Convention Sunday. Delegates passed a resolution to have the Leap Manifesto included in deliberations about the future direction of the party. (Jason Franson/Canadian Press)

'When you move up from manifestos'

"We're acting, really acting, on the basis of a concrete plan that is actually being implemented," Alberta Premier Rachel Notley told convention delegates on Saturday afternoon. "That is what you get to do when you move up from manifestos, to the detailed, principled, practical plans you can really implement by winning an election."

This was the thunderous challenge at the heart of a remarkable speech that seemed mostly well-received. Less than 24 hours later, the convention went ahead and adopted a resolution to continue considering the Leap Manifesto anyway.

Granted, the commitment is only to discuss the manifesto. New Democrats aren't inviting the Leap Manifesto to move in, they're merely letting it crash on the couch. But unless or until the federal NDP repudiates this aversion to new pipeline construction, it will be at odds with the most important New Democrat in the country, Notley.

Manifesto proponents might claim their own practicality — the need to confront the threat of climate change — but to oppose the proposed Energy East pipeline, for instance, would also put them offside with the current majority of opinion of Canadians. Or perhaps they imagine that Canadians can be convinced to leap in a different direction entirely.

'Don't let this very divided vote divide us, let's all work together now to choose the best person to take our project forward,' says Tom Mulcair 5:51

The pipeline challenge

It is tempting to present this as a particular problem for the federal NDP, another flash of tension between principle and power. But even if it is, it is also something like the challenge that confronts Justin Trudeau's Liberal government; similar too, to the issue that bedeviled Stephen Harper's Conservatives.

With Keystone XL, pipeline development became the signal issue of environmental concern. And, in Canada, questions of climate change and science are compounded by economics, federalism and internal tension. Energy East might be desired in Alberta and New Brunswick, but it is opposed in Quebec. A pipeline might be the safest way to transport oil, but every so often a pipeline springs a leak. Economic prosperity might be desired, but in the absence of a plan for climate change it can seem dangerous.

This might all yet get tied up in a neat little bow somehow. In the meantime, New Democrats might only be having their own version of the national conversation.

In search of a common thread

Brian Topp, former adviser to Jack Layton, runner-up to Mulcair in the NDP leadership of 2012 and now chief of staff to Notley, surveyed the scene Monday in a Facebook post and saw the New Democrats as "serious" players in Quebec and Alberta, alongside traditional bases in British Columbia, Saskatchewan, Manitoba, Ontario and Nova Scotia.

"Federal politics is about finding the thread that unites the pearls. That's hard to do, which is why so few people are really successful at it," he said. "And yet Canada works, better than most countries. Being a compelling political offer in all regions of the country, in both official languages, is the real issue we all need to be thinking about over the next two years. It will be work worth doing."

Maybe a pipeline is the thread. Maybe the Leap can be fashioned into a thread. Maybe the manifesto can be wrapped around a pipeline to tie this all together.

New Democrats have quaintly invited a debate amongst themselves. In choosing the next NDP leader, the brothers and sisters get to make some interesting decisions.