Subject to change

Jeffrey Simpson nicely summarizes the target demographic for the Cons' substance-free attack ads:

An even more important group is what we might pejoratively call the ill-informed and uninterested. These are voters who don’t follow politics, don’t track issues, are aware only in the vaguest way of what governments do (except levy taxes) and make up their minds (if they vote at all) largely on the basis of image and impressions of party leaders. These are often “swing” voters in that they don’t have anchors in partisanship or issues. They’re heavily influenced by what they see on TV, since they get almost all of their political information from that medium.

When, for example, the Conservatives were holding focus groups before their first attack ads against Liberal Leader Michael Ignatieff, they found that voters were only vaguely aware he’d spent a lot of time outside Canada. When respondents discovered how long he’d lived abroad, they became decidedly more negative. Hence, the attack ads’ focus on the length of time Mr. Ignatieff was out of Canada.

But the flip side looks to be just as important as the status quo: the less people who are "ill-informed and uninterested", the less incentive parties will see to attack minor personality traits rather than spending more time dealing with real issues. And while Simpson is unfortunately right that the current tactical arsenal doesn't figure to change in the near future, it's well worth working on engaging the broader public in other ways so that attack-ad trivia doesn't look like such an effective means of shifting votes.