The Conservatives have "a marginal advantage" in support over the Liberals, with a four-point lead over their rivals, according to a new poll.

The Nanos Research poll, which looks at committed voters and will be released Thursday, shows the Tories have managed a slight boost since Parliament resumed this fall (difference from a September poll in brackets):

  • Conservatives: 36.6 per cent (+ 3.3)
  • Liberals: 32.4 per cent (- 0.4)
  • NDP: 16.3 per cent (+ 0.7)
  • Bloc Quebecois: 9.8 per cent (- 2.3)
  • Greens: 4.9 per cent (- 1.3)

"For the Tories, last month was a very controversial month, and it was a statistical and actual dead-heat," pollster Nik Nanos told CTV News Channel's Power Play on Wednesday.

The government's decision to cut the mandatory long-form census, and fallout from the Guergis affair, eroded the Tories' sizable lead over the summer, according to Nanos.

The Conservatives now have a lead of 4.2 percentage points, which is just outside the poll's margin of error -- the results are within 3.4 percentage points, 19 times out of 20.

"What we see now is a marginal advantage of four to five percentage points on the national ballot front, so it's a little bit of a reprieve," Nanos said.

But he cautioned that the poll was conducted between Oct. 1 and Oct. 7 -- before Canada lost its bid for a temporary seat on the United Nations Security Council, and the Conservatives announced a $55.6-billion deficit.

"We'll have to wait and see whether all these new issues kind of slap them back down to a dead heat with the Liberals," Nanos told Power Play.

He also noted that support for the Liberals has remained stagnant, with leader Michael Ignatieff unable to take advantage of any perceived mistakes by the Tories.

"They've basically been at the same level of support for the past month," he said. "That means they haven't been able to significantly capitalize on the controversies that have occurred in the public domain, and that voters aren't really flocking to them at this point in time.