OTTAWA - Conventional wisdom suggests Stephen Harper must be mad to thrust the country into an election at a time when he has little hope of winning a majority.

The prime minister himself has acknowledged that public opinion polls "aren't particularly wonderful."

"My expectation is that we will have another minority," Harper said Wednesday in Tuktoyaktuk, N.W.T., where he's on a three-day, campaign-like swing through the Arctic.

So why have an election?

"It gives the government a fresh mandate that will give the government another couple of years to proceed," said Harper.

A former chief of staff to Harper suggests there's more to this seemingly self-evident, benign response than meets the eye.

Tom Flanagan, a political scientist at the University of Calgary, believes Harper would be satisfied to return with a strengthened minority -- a result that would throw the Liberals into chaos, thereby advancing the prime minister's longterm strategy of destroying Canada's so-called natural governing party.

"I don't think Harper has to be thinking about a majority at all," Flanagan said in an interview.

"Strategically, this is sort of a prolonged war of attrition."

As Flanagan sees it, the first major battle in this incremental war occurred in 2004, when Harper managed to reduce Paul Martin's Liberals to a minority. In the second clash in 2006, Harper won his own Conservative minority.

The third skirmish, which Harper appears set to launch next week, likely won't kill what Flanagan jokingly refers to as "the evil empire." But, if the Tories can win a few more seats at the Liberals' expense -- an outcome Flanagan considers realistic given Harper's superior campaign skills and the Tories' fatter war chest -- he predicted that would be enough to throw the Grits into a longterm tailspin that could eventually lead to their demise.

"You can fight a war with some objective less than total victory," he said of the coming campaign.

If the Liberals lose even a handful of seats, Flanagan predicted they'll immediately dump Leader Stephane Dion, a forecast echoed privately by plenty of Grits. The party would have to embark on a costly leadership campaign before most contenders from the last contest, including Dion, have paid off their leadership debts.

Moreover, a reduction in popular vote would mean the already cash-strapped Liberal party would get less money in election expenses rebates and in its annual public subsidy. Flanagan said that could make it difficult for the Liberals to pay off any debts from the coming election campaign and harder to secure bank loans for a future campaign.

Hence, he concluded, another Tory minority "would be enough to throw the Liberals into turmoil and give Harper . . . a virtually free hand in Parliament for quite a while and really handicap his main opponent."

Not surprisingly, Dion and other opposition leaders have a different assessment of Harper's strategy.

They contend the prime minister is inventing excuses for an early election strictly because he fears Tory fortunes will plummet over the fall as the government is hit with further bad news about the sluggish economy and various alleged ethical lapses.

They charge that Harper wants to pre-empt parliamentary committee hearings into the so-called Cadman affair and Tory party spending irregularities in the 2006 campaign.

And, they say, he wants to get the vote out of the way before Julie Couillard releases her tell-all book on Oct. 14, which promises more juicy details about her biker gang past and how her former relationship with Maxime Bernier ended in his resignation as foreign affairs minister.

Flanagan doubted such potential landmines -- which he believes could be easily defused -- are directly influencing Harper's decision to pull the plug on his government.

However, he said Harper would rather call the election himself, on his own timing and terms, than wait for the combined opposition parties to topple the government later this fall over some trumped up scandal.

"He doesn't like being at the mercy of others. He likes to be in control of what he's doing."

As plausible as the various theories on what's motivating Harper may be, Tory insider Bob Plamondon suspects only one thing would push Harper "over the edge" into an election: the prospect of winning a majority.

"I suspect that there's some pretty strong or in-depth party polls that are riding by riding, that are persuading him that his chances are pretty good right now," said Plamondon, author of a soon-to-be-released book chronicling the successes and failures of the Conservative party since Confederation.

"There may be some inner confidence that they can move those numbers closer to a majority."