By Mike Dorning

Despite all the jokes about slash-and-burn political ads, television commercials in the presidential campaign have been overwhelmingly positive, according to a study to be released today by the University of Wisconsin Advertising Project.

Ninety percent of commercials aired so far in the presidential campaign were judged “positive,” which the research team defined as speaking solely about the candidate or their policies. Just 10 percent were judged to have any negative content at all, according to the study, conducted by the University of Wisconsin Advertising Project and funded by the non-partisan Joyce Foundation based in Chicago.

Democrat John Edwards, who dropped out of the race this week, was the rare exception. The study found 81% of Edwards’ ads were contrast ads and in virtually all he criticized Obama and Clinton. “So, while most attention in free media went to flare-ups between Clinton and Obama,” said Ken Goldstein, a University of Wisconsin political science professor and primary author of the study, “Edwards was most likely to focus on his competitors in paid media."

The study, which covered broadcast television ads aired through last Sunday, offered an overview of a campaign air war that has been highly competitive on the Democratic side but remarkably lopsided in the Republican field.

Republican Mitt Romney, a former investment manager who dug deep into his own portfolio to fund his presidential campaign, has dominated the airwaves on the GOP side, spending more on television commercials than all of his rivals combined.

Romney aired $28.9 million in broadcast television ads versus $8 million in commercials for McCain, the Republican candidate with the next largest total. Rudolph Giuliani, who dropped out of the Republican race this week, aired $5.6 million in television ads. Ron Paul followed with ads worth $2.8 million. Mike Huckabee aired ads worth $2.6 million.

On the Democratic side, the two well-funded frontrunners have maintained a rough parity. Obama has led the Democratic field so far, airing $22.7 million worth of television ads versus $18.7 million for rival Hillary Clinton.

Edwards, who lagged the others in fundraising, aired $8.3 million in ads.

Through Sunday, only $8 million had been spent in Super Tuesday states on TV – $3 million of it in California, the state with largest cache of delegates – yet nine days out from the New Hampshire primary, $26 million had been spent there and at the same point before the Iowa caucuses, $36 million had been spent there.

The study used data obtained by the TNS Media Intelligence Campaign Media Analysis Group (TNSMI/CMAG), a firm that tracks public policy advertising.