Who's in opposition?
In point of fact, in past elections, negative attack ads used by governing parties has resulted in those parties gracing the opposition benches following the election. The Kim Campbell Tories and Martin Liberals all ran negative ads against their opposition and both ended up out of power. The way the Harper Tories have been acting this week, it looks like they're back in opposition of a Liberal government. It shows to some extent that the Tories have lost the ability to define the agenda and are desperately trying to cast aspersions onto someone else in order that the voter doesn't notice that Harper and Co. have been spinning their wheels for the past few months. It's a very risky move for a government to do this given the track record of governments that have tried.
I can understand why the Tories are doing it though. Their poll numbers are down outside of Alberta and they need to change that and fast. The more the Conservatives sink, the more likely the opposition will pull the plug on them. Further, there is some urgency to define Stephane Dion in the minds of Canadians before the Liberals can. Normally a party in power would be subtle about doing this. Being subtle, something the Tories aren't good at to begin with, probably wouldn't bring results quickly enough. So Harper and Co. are going with what they know which has all the subtlety of a sledgehammer. After all, sledgehammer tactics work well on the voters back home in Alberta. The Conservatives strategy is more likely to backfire on them though, given that they need to win the election outside of Alberta. In the rest of Canada, attacks like what the Tories are dishing out just make them look mean at best and desperate at worse. This isn't going to get voters back to them in the droves the Tories need.
Time and the polls will tell how successful the Tories are with their attacks. I would expect that this ham-fisted approach will fail to draw the support the Conservatives have lost back, and definitely won't attract new converts. A more subtle approach would have worked better over time for Harper and his government. At the least it wouldn't make Harper look like he's trying to get back into Stornoway.