OTTAWA - Today's federal election stands to make history -- and not just because Stephen Harper is on the cusp of joining John A. Macdonald and John Diefenbaker as the only Conservatives ever to win three consecutive terms in office.

The fate of the prime minister, and whether he wins his coveted majority government, will only be part of the enduring tale from tonight.

It's on the opposition benches where history is likely to ring twice.

If the polls are to be believed, the NDP could achieve a pair of once-unimaginable feats: overtaking the Bloc Quebecois as the No. 1 party in Quebec, while supplanting the Liberals as the No. 2 party nationally.

Either of those events could signal a seismic shift in Canada's political landscape.

The tremors could be temporary, like the ephemeral successes of Ontario's NDP and Quebec's ADQ. Or they might be more permanent, like the extinction and replacement of B.C. and Alberta's Socreds, Saskatchewan's Conservatives, and Quebec's Union Nationale.

It appears almost inevitable, however, that a nation that sleepwalked into what seemed five weeks ago like a snoozer of an election will wake up tomorrow to a new national conversation.

Would different economic debates surface with a powerful NDP? Would its batch of Quebec rookies demand tougher environmental laws? How would such debates affect East-West relations? What about Quebec nationalism? Foreign policy? Some will talk about uniting the left, changing the Senate, and what about the NDP's longstanding dream of proportional representation in the House of Commons?

All these could receive a jolt from the new dynamic.

At the national level there have been three major realignments in Canada's past: the elections of 1896, 1984 and 1993, according to political historian John Duffy. Those elections not only marked changes in government but also the rise and fall, over a longer period, of major political parties.

Each of those shifts -- the dawn of Liberal dominance under Wilfrid Laurier, the Mulroney landslide that ended a century of Liberal hegemony in French Canada, and the emergence of a balkanized Parliament fractured along regional lines -- shared one common epicentre: Quebec.

"I think this is going to be a big one," said Duffy, a Liberal partisan who authored the book 'Fights of Our Lives,' which chronicles the federal elections that served as key historical turning points.

"The realignments of this country tend to happen when Quebec picks a new lane. That appears to be what's happening here."

He cites past examples of how Quebec flexed its political power and exerted influence throughout Confederation.

The socially conservative, anti-communist Quebec of the 1930s and '40s held back Mackenzie King's Liberals from expanding the welfare state. When Quebec swung to the left in the 1960s, the Pearson-Trudeau Liberals responded by introducing social programs like the Canada Pension Plan and medicare, along with justice legislation that famously booted the state from the nation's bedrooms.

The extent of any new, Quebec-based NDP influence might be curtailed somewhat if the Tories take home a majority.

Harper set out to achieve that task with ruthless discipline in a campaign where he limited his exposure to non-partisan crowds and the national media, stickhandling around scandals to focus on a simple, repetitive message: the opposition equals instability, and a Conservative majority doesn't. He weathered attacks that he abused power for partisan purposes, blew a historic budget surplus, and ignored people's everyday priorities while boosting military funding and building prisons.

It would be the first Conservative majority since 1993 -- since that most recent historical realignment. The subsequent decades have been marked by the regional grievances that erupted in that era.

Since the 1990 failure of the Meech Lake accord, the Conservative party has split in two and reunited. The Bloc, meanwhile, has largely hounded successive governments over alleged federal transgressions against Quebec: the failure of Meech, the Clarity Act, the sponsorship scandal, the federal-provincial fiscal imbalance, funding cuts for arts groups, and accusations of favouritism any time the federal government offered cash for Newfoundland's hydro industry, for Ontario's auto sector, Manitoba's flood victims, Alberta's oil sands and B.C.'s HST taxpayers without offering equal support to their Quebec equivalents.

Over six straight elections, the Bloc not only won the lion's share of Quebec seats but exerted additional influence by making it mathematically tougher for any national party to form a majority government.

"This very well has been the era of the Bloc Quebecois -- and the era of Quebecers' absence from national politics," Duffy said.

"Having Quebec more directly engaged will change everything." He quipped that modern Canadian politics has been starved of "French power," the term used in the Pearson era to describe prominent MPs like Pierre Trudeau, Jean Marchand and Gerard Pelletier.

He predicts that a stronger NDP stacked with Quebec MPs would inevitably make the environment a central issue in a reconfigured Parliament.

But he warns that any orange tide tonight should not be over-interpreted as a clear win for Canadian federalism. Quebec, after all, will continue electing sovereigntist MPs; the NDP, for its part, is relying heavily on promises to nationalists that might prove controversial elsewhere in the country.

Pollster Allan Gregg had a front-row seat to the great realignment of 1993, when he worked for the imploding Progressive Conservative party.

He doubts Canada is witnessing a similarly sweeping shift this time.

"On the surface, it does not appear to have the potential to change the political landscape for the same duration as 1993 did," said Gregg, the chairman of the Harris-Decima firm.

"That (1993) river breaks to this day and, basically, it resulted in the eradication of the Progressive Conservative party."

It might not be a repeat, then, of examples from B.C. and Alberta, where Social Credit parties were supplanted by Liberals and Progressive Conservatives; from the Union Nationale, which was replaced by the Parti Quebecois; and the Grant Devine Tories, who gave way to the Saskatchewan party.

It might be more like the Ontario NDP -- which, after winning a 74-seat majority government under Bob Rae -- has won barely half that number, an underwhelming grand total of just 43 seats, in the four elections held since 1995.

Perhaps it might be like the Action democratique du Quebec, the Mario Dumont-led upstart that pushed the PQ to third place and nearly defeated Jean Charest's Liberals in 2007, rendering them to a minority. Within a year, Dumont's crop of ill-prepared rookies had become a laughingstock. Charest had won back his majority. Dumont's party was reduced to seven seats, he resigned on election night, and his ADQ remains on the endangered-parties list.

In the next breath, however, Gregg mentions three potential long-term consequences of tonight.

More pro-Canada MPs might actually help separatists in Quebec create an us-against-them confrontation versus Ottawa, he said. Or maybe more Quebecers will become engaged in national debates. And perhaps a shocking result will create momentum for the New Democrats and Liberals to merge.

"So in that respect," he concludes, "I think it may (be historic)."