The New Democratic Party is doing something I would never have thought possible when I covered its founding convention in Regina in 1961.

This weekend, they are choosing not just a new leader but someone who will head the opposition parties in Parliament.

For the first time that puts the party realistically in line to form a government if they can win a difficult contest on three fronts in Quebec, against the Liberals, and against the Conservatives under Stephen Harper.

In the years since the party was founded to replace the old CCF, they have formed provincial governments everywhere in the West except Alberta, in Ontario and in the Atlantic provinces, however, the big prize of national power has eluded them.

It was the iconic figure of Tommy Douglas, the father of national healthcare, who set the party on its way as one dedicated to social fairness and economic justice. But Tommy and later leaders could never move it beyond its image as a big-spending socialist-labour coalition. Although, Ed Broadbent came closest to breaking that stereotype.

It was left to Jack Layton to take it to a new level by retaining the party's popular values but tying them to optimism and most of all, pragmatism and compromise when necessary.

He also transformed it into a modern political organization capable of winning elections.

This weekend, the party is trembling on the brink knowing, as all its members do, this may be their moment in history if they make the right choice about their next leader.

They are voting against the background of a Nanos poll indicating that a near-majority of Canadians say the country would be in good hands under an NDP government and another from Environics showing the party's national support is equal to that of the ruling Conservatives.

The question for the NDP rank-and-file is: who best to carry forward and consolidate what many believe is the party's momentum? We will have the answer by the time CTV's Question Period goes on air Sunday morning and our program will be fully devoted to the new leader and where the party and its Conservative and Liberal opponents believe they are all at.