Attack ads and the law of unintended consequences

So the Conservatives have spent $36 million making Ignatieff toxic in the eyes of voters who are gullible enough to believe such dreck.  But what happens if the majority of Canadians who despise the Conservatives are motivated to vote against Harper?  They are innoculated against voting for the Liberals.  So they turn to the one Leader that Harper would like to see elected less than Ignatieff.  As the pundits say, politicians use attack ads because they work.   But not always they way the attacker intended.