A poll has Prime Minister Stephen Harper towering over the two main contenders to his throne on the issue of who would be the best national leader.

In the SES poll, Harper was picked by 42 per cent of respondents.

The shocker had Liberal Leader Stephane Dion in a virtual tie with NDP Leader Jack Layton, at 17 per cent and 16 per cent respectively.

Pollster Nick Nanos, who conducted the poll for Sun Media, told Â鶹´«Ã½net's Mike Duffy Live that he thinks three factors are in play.

"I don't think we can underestimate the impact of the negative ads, because the Conservatives have been getting their message out, and the Liberals -- for all intents and purposes -- have been silent," he said.

The Conservatives have run attack ads in both English Canada and Quebec portraying Dion, who won the party's leadership in December, as weak and indecisive.

"There was a real missed opportunity for the Liberals. Their numbers peaked right at the Liberal convention, but they weren't able to use that to launch any type momentum," he said.

"Finally, for Stephane Dion, he's been too silent. ... The Conservatives have drawn a picture of Stephane Dion for Canadians, and there's been nothing as a counterpoint to that," Nanos said.

Paradoxically, he thought it would take the Conservatives to turn things around for Dion.

In the 1993 federal election, Jean Chretien was being described as a tired Trudeau-era guy and yesterday's man, Nanos said.

The Conservatives went after him with a negative ad that asked "Is this the face of a prime minister?"

"All it took was one negative ad that went too far," he said.

If the Conservatives go too far in attacking Dion, "it could boomerang and help (him)," Nanos said.

Greg Weston, parliamentary columnist for the Ottawa Sun, told MDL that incumbency always gives the prime minister a boost in such polls.

Even with that caveat, however, going carefully through the details of the poll shows nothing but bad news for Dion, he said.

"In every single age group demographic -- age group, men and women -- Stephane Dion was virtually nowhere to be seen," he said.

Harper was the second choice of virtually every other party group, including the Greens, he said.

"In some cases, it was kind of bizarre. ... When you asked people who said they intended to vote for the Green Party, their first choice was (Leader) Elizabeth May -- and Stephen Harper," Weston said.

Dion has tried to stake his political persona on being a green politician.

Jane Taber, senior political writer with The Globe and Mail newspaper and co-host of CTV's Question Period, said she talked to the Liberals about this poll.

"The Liberals are saying this is the reason they have Stephane Dion out on the road -- he needs to be known," she told MDL.

When an election comes, he will pick up support because the leaders come into focus, she said.

Despite the leadership gap, the Liberals and Conservatives remain relatively close in support for their parties:

  • Conservatives - 36 per cent
  • Liberals - 33 per cent
  • NDP - 16 per cent
  • Bloc Quebecois - 10 per cent
  • Green Party - 6 per cent

The polling was conducted between March 31 and April 5, with 931 respondents. The margin of error is 3.2 percentage points, 19 times out of 20. 

Nanos said no one appears to be able to break the deadlock between the Liberals and Conservatives that would allow one of the parties to form a majority government.

"These elections are getting more and more expensive for everybody," he said.