Obama airing more negative ads, but McCain is more maliciously untruthful.

Advertising experts on this year's political ads. Interesting stuff.

Seventy-seven percent of Obama's ads the week after the Republican Convention were negative, compared to McCain's 56 percent, according to a recent study by the University of Wisconsin, cited the moderator, USA Today Washington bureau chief Susan Page, at a Pulse of America discussion.

And the attack ads are damaging both candidates in the eyes of the public.

"Both of these campaigns have diminished whatever their message might be," said Republic consultant and strategist Ed Rollins, who was political director for Ronald Reagan in 1984, and this year served as campaign manager for Mike Huckabee.

Reviewing McCain's controversial commercial telling voters that Barack Obama supported sex education for kindergarten kids, the panelists agreed that the ad was a misstep.

"Obama is being pretty negative in some of his ads, but the overall impression is that McCain is playing fast and loose with the truth," said Democratic consultant and strategist Bob Shrum, who worked on the failed presidential bids of Al Gore and John Kerry. "The biggest effect of the McCain advertising right now has been sullying the McCain brand. And as anyone in this room knows, if your ad is hurting your brand, it doesn't matter what else you are getting out of it."

Despite challenges from the press, the McCain campaign has continued to take a sensational approach in its ads, Rollins said. "It has damaged McCain. You can say negative things about your opponents as long as they are truthful, but it's a fine line."

Obama's ads have also been negative, but such efforts -- like the spot depicting McCain as out of step and computer illiterate -- were driven by strategy, said Shrum, while McCain relies on "tactics and misdirection. Whatever has occurred to them at a given moment becomes an instant ad."