A brief note on public opinion polls
Lib 35%, CPC 30%, NDP 20%, BQ 11%
PC 36%, Lib 33%, NDP 8%, Ref 11%, BQ 10%
Lib 48%, PC 39%, NDP 11%
Those are the final pre-election polls for the three most recent times Canadians voted out an incumbent government (Jeff has more on the 2005/06 election here).
In all three instances - 2005/06, 1993, and 1984 - the incumbent party led when the writ was dropped. Twice, they fell by 20 percentage points during the campaign.
In fairness, the incumbent party has also led the past five times they were re-elected. Obviously, it's better to be 10 points up than 10 points down.
But campaigns matter. Let's not forget that.