Stephen Harper's Conservatives are asking a judge to throw out all evidence provided by pollster Frank Graves in support of a legal bid to overturn Tory election victories in seven federal ridings.The Conservatives say Mr. Graves, president of Ekos Research, is unfit to be an expert witness because, they charge, he's biased against their party.

Rather than being an impartial source, they allege in a notice of motion filed on Sept. 11 in federal court, Mr. Graves is "personally invested in the narrative that voter suppression did take place."

Mr. Graves has conducted a poll that he says demonstrates strong evidence of a targeted program of voter suppression aimed at non-Conservative voters during the campaign for the May, 2011, federal election.

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His research is central to a legal challenge underwritten by the left-leaning Council of Canadians that alleges misleading robo-calls or other harassing phone messages interfered with fair elections in ridings from Yukon to Toronto.

On Thursday, the Ekos president called the Tory motion defamatory, saying the Conservatives have sketched a false portrait that tries to undermine his ability to draw conclusions from his research. He said he's strongly considering legal action in response.

"They think I'm some pollster hack, but my curriculum vitae will clearly document that I have a very strong background in these areas," Mr. Graves said.

Mr. Graves's survey found Canadian voters in the seven ridings were 50 per cent more likely to say they had received illegitimate calls than those in 106 surveyed "comparison" ridings, many of which had no reports of illegal calls.

About three times as many Liberal, New Democrat and Green supporters as Conservative supporters claimed they were given false or incorrect information about polling station locations in the last two or three days of the campaign, Ekos found.

The Tories allege that Mr. Graves is offering testimony – a summary of his findings that he submitted as evidence – that goes far beyond his area of expertise in statistics.

They note he describes himself in his curriculum vitae as expert in 14 areas, including immigration, arts and culture, tourism, Indian and northern affairs and transportation.

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"Given the remarkable breadth of the above claims, it is apparent that Mr. Graves does not possess any special expertise beyond the knowledge of a trier of fact," the motion says, referring to the role usually played by a judge or jury.

"[His] perception of himself as an 'expert' in such a multitude of areas gives rise to a concern that he will testify about subjects on which he has no expertise."

In a direct attack on his impartiality, the Tories suggest Mr. Graves is somehow in league with their opponents, alleging that his firm received more than $61-million in contracts from the federal government when the Liberals were in power "and has much less revenue from that source since the Conservatives were elected."

The Conservatives also took issue with the pollster's use of the Internet messaging program Twitter to broadcast updates on the court case.

"It is evident from Mr. Graves' frequent publishing of media coverage of the current application that he considers his role to provide independent assistance to the court secondary to his interest in generating publicity for himself, his business and the applicants' cause."

Speaking Thursday, Mr. Graves said these attacks are unfounded. He noted his firm has won all its work in open competition and that Ekos ranked second last year as a market research supplier to the Harper government.

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"I've served, reported to, and advised all shapes and forms of governments for 32 years," he said. "Apart from this particular administration, I've never had anybody accuse me of bias."

The Conservatives also noted Mr. Graves' Twitter account, "@VoiceOfFranky," which they allege "contains numerous conversations where his dislike of conservatives appears to overcome the professional interest he has in remaining neutral in public communications."

Mr. Graves, in response, said he's been very careful not to show partiality to one particular party.

He said on Thursday the Tories were referencing an incomplete copy of his CV and that an updated one is ready.

The controversy over fraudulent robo-calls has focused largely on the riding of Guelph, which Elections Canada is investigating.

Efforts launched this spring to annul the election results in seven ridings, filed last month by nine voters, argue that misleading, harassing and fraudulent calls made during the campaign had a clear impact on the results, targeting non-Tory voters in a bid to help the Conservative candidate.

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The seven ridings named in the motions are: Yukon, Nipissing-Timiskaming in Ontario, Elmwood-Transcona in Manitoba, Saskatoon-Rosetown-Biggar, Winnipeg South Centre, Don Valley East in Toronto and Vancouver Island North.

All were won by Conservative candidates by margins of 1.3 per cent of the total vote or less, with the exception of the B.C. riding, which the Conservative candidate won by 3 per cent.