The Conservatives have a strong lead with 39 per cent support ahead of a possible spring election, according to a new poll, despite the opposition parties hammering away at the Tories on ethics issues.

With seemingly all signs pointing to the government's fall, a new Nanos Research poll for CTV and the Globe and Mail shows that support for the Conservatives is 11 percentage points ahead of the Liberals.

Pollster Nik Nanos said the results suggest that if an election were held today, "Canadians could spend $300 million… and we still have a very similar outcome" to the 2008 vote.

The telephone survey of committed voters was conducted between March 12 and 15, a few days after House Speaker Peter Milliken ruled against the government on two issues of Parliamentary privilege.

When respondents were asked which party they supported, about 39 per cent said Conservative. Here are the results (percentage-point change from last month in brackets):

• Conservatives: 38.6 per cent (-1.1)
• Liberals: 27.6 per cent (+1)
• NDP: 19.9 per cent (+1)
• Bloc Quebecois: 10.1 per cent (+0.2)
• Greens: 3.8 per cent (-1.1)

However, the Nanos Leadership Index suggests that the raucous atmosphere on Parliament Hill -- with a rash of scandals and attack ads in the past month -- may have had a negative impact on Prime Minister Stephen Harper.

The index looks at how committed voters rank the leaders on three main qualities: trust, competence and vision.

When respondents were asked which leader they thought was the most competent, Stephen Harper dropped by 7 percentage points from last month:

• Stephen Harper, Conservative: 29.8 per cent (-7.1)
• Jack Layton, NDP: 15.9 per cent (+3.8)
• Michael Ignatieff, Liberal: 12.5 per cent (-0.2)
• Gilles Duceppe, Bloc: 8.6 per cent (+1.7)
• Elizabeth May, Green: 3.4 per cent (+0.8)
• None / Undecided: 29.8 per cent (+0.9)

When respondents were asked which leader they viewed as the most trustworthy, Harper had a slight decline from last month's poll, although still within the error of margin. But nearly a third of respondents were either undecided or chose none:

• Stephen Harper, Conservative: 26.6 per cent (-2.5)
• Jack Layton, NDP: 17.2 per cent (+0.5)
• Michael Ignatieff, Liberal: 12.7 per cent (+1.8)
• Gilles Duceppe, Bloc: 8.5 per cent (+0.8)
• Elizabeth May, Green: 4.3 per cent (+1.5)
• None / Undecided: 30.6 per cent (+0.8)

On the issue of which leader had the best vision for Canada's future, Harper also showed a drop:

• Stephen Harper, Conservative: 26.4 per cent (-6.5)
• Jack Layton, NDP: 18.3 per cent (+3.5)
• Michael Ignatieff, Liberal: 14.5 per cent (+1.2)
• Gilles Duceppe, Bloc: 4.4 per cent (+1.3)
• Elizabeth May, Green: 3.9 per cent (-0.4)
• None / Undecided: 32.5 (+0.7)

Results from those three questions are compiled for the Leadership Score Index. It has Harper again in the lead -- but down 16 points:

• Stephen Harper, Conservative: 82.8 (-16.1)
• Jack Layton, NDP: 51.4 (+7.8)
• Michael Ignatieff, Liberal: 39.7 (+2.8)
• Gilles Duceppe, Bloc: 21.5 (+3.8)
• Elizabeth May, Green: 11.6 (-1.1)

However, the Nanos poll suggests party policies, and not the strongest leader, may decide the next federal election.

Respondents were asked which factor was most important in influencing their vote: the local candidate, party policies, the party leader, or their traditional support for a party. Only 20 per cent said it was the leader:

• Party policies: 40 per cent
• Party leader: 20 per cent
• Local candidate: 12 per cent
• Traditional support: 10 per cent
• Unsure: 10 per cent

Those results suggest that "Canadians are looking for ideas to kind of latch onto, in terms of where Canada should go in the future," Nanos said.

Methodology

• The survey involved 1,216 Canadians 18 years of age and older
• It was conducted between March 12 and 15
• Results are accurate to within 2.8 percentage points, 19 times out of 20
• For the Leadership Score Index, data was weighted for gender and age to match Canadian census results