Stephen Harper wrapped up his fourth bid for a majority government with a call for Canadians to vote Conservative to keep the NDP away from the levers of power, a refashioned pitch that tries to exploit Jack Layton's risen political fortunes.

The NDP leapfrogged Michael Ignatieff's Liberals in opinion surveys during the fifth week of the race, a development the Conservative Leader argues has opened the door for Mr. Layton to form a coalition government should the Tories fail to secure a majority.

A party needs to win at least 155 seats to win a majority in Monday's election.

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Mr. Harper has reworked his campaign message in the final week however to try to spook undecided voters into rallying to the Tories to stop Mr. Layton, a rival he at one point suggested was selling "smiles and snake oil."

Exhibit A for the Conservative Leader are the Bob Rae years in Ontario. The Tories are hoping bad memories of the early 1990s NDP government will scare the electorate .

"Ontarians know from bitter experience how devastating it can be for workers and families when an inexperienced NDP government suddenly finds itself in office," Mr. Harper told a crowd of more than 400 at a London, Ont. rally Sunday.

"[It's]folksy talk, grandiose promises from an untested party on the campaign trail - soon to be replaced by the sobering reality of crushing taxes, out of control deficits [and]massive job losses."

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While Mr. Harper has rewritten his campaign pitch to target Mr. Layton, the heart of his message to voters remains the same hypothetical scenario. Unless the Tories are granted control of the Commons, he's warned since March 26, his rivals will unite to displace him and take power themselves in a coalition or alliance - one that favours more taxes and government spending and risks jeopardizing the economy.

In the last week he's shifting to arguing Mr. Layton would lead what he calls a "ramshackle coalition" to cut short the tenure of a Tory minority government.

It's far from clear though how the election will play out and the fortunes of all major political parties will depend on tight-three way races in dozens of ridings Monday.

The Conservative Leader refused to speak to the national media on his campaign plane Sunday. It was an effort to narrow the media's focus to his comments in speeches during a final dash across the country and reflects the restrictive approach he's taken to questions from journalists all through the campaign.

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Mr. Harper began Sunday with a rally near Charlottetown, PEI before stopping briefly in London, Ont. and then ending the campaign with a gathering of party faithful in the Lower Mainland city of Abbotsford, B.C.

The Conservative Leader normally shies away from publicly analyzing politics, but on Sunday he paused to take stock of the changing fortunes for parties such as the NDP.

The NDP's climb to first place in public support in Quebec, for instance, changed the dynamics of political races in a province where the Tories are used to battling "This has been an unusual election," the Conservative Leader admitted to a group of more than 550 party faithful in Stratford, PEI, near Charlottetown.

When Mr. Harper began the campaign 37 days ago, the chief target of his stump-speech attacks was Michael Ignatieff.

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By Sunday, however, the Conservative Leader was attempting to write off the Liberals and steal their support with his stop-the-NDP pitch.

"The best hope for Mr. Ignatieff now is to be a back seat passenger in an NDP government."

He urged Liberals to read the New Democrat program "A vote for the Liberals is now a vote for an NDP government," Mr. Harper told Londoners at Sunday's rally.

"Let me speak very clearly to traditional Liberal voters: I know many of you do not want NDP policies. That you do not want NDP tax hikes," he said.

"That is why to make sure the economy stays on track for all of us, and the next Parliament does not raise taxes, Canada needs a stable, majority Conservative government."