Alex Massie thinks "this Canadian Conservative hit on Michael Ignatieff is great." What Canadian populism sounds like:
Yglesias ponders the impact of attack ads in multi-party systems:
The interesting thing is that in a multi-party system it's difficult for the party behind an attack ad like this to reap all the benefits. This makes Ignatieff and the Liberals look terrible, but depending on your ex ante political preferences thinking worse of Ignatieff could turn you into a voter for the separatist Bloc Québécois or the social democratic NDP rather than the center-right Conservatives.
Joshua Tucker looks for research on the subject and comes up empty.
The Dish 