That’s what the McCain campaign has been doing and the proof is in their ads. The AP has done a study on this:

MADISON, Wis. – Nearly every TV ad Republican John McCain ran last week was negative, compared to just 34 percent of those by Democrat Barack Obama, according to an analysis released Wednesday.

The harsher tone in McCain’s ads mirrors the sharper attacks he and his running mate Sarah Palin have been making on the campaign trail as polls show Obama opening up a lead.

During a week of economic turmoil and American’s seeing trillions in their retirement dissolve into the abyss, John McCain could not muster what it takes to be a leader. Instead he had to resort to the tactic Americans have come to despise – attacking your opponent. If that’s “change you can believe in” then I don’t think we need it.