With just hours left before the Iowa Caucuses, the intensity of one-on-one campaigning is high, with six candidates set to hold events in the state Monday. But the candidates and their allies have been trying to reach Iowans in their cars and homes, too, with a barrage of advertising on radio and television.

A recent Des Moines Register analysis concluded more than $10 million was spent on campaign ads — in the month of December alone. But the ad wars began in June; Michele Bachmann was among the first on the air.

Iowa State University professor Dianne Bystrom has analyzed campaign ads in the past. In reviewing this year’s set of Caucus contenders, Bystrom sees a clear difference in the Ron Paul 2012 campaign ads compared to what Paul ran here four years ago.

“He has a new ad consultant. His name is Jon Downs. he’s out of Washington, D.C. He’s actually a moderate Republican, so that’s kind of interesting,” Bystrom said during an interview with Radio Iowa. “He probably the best-produced, edgiest ads in the campaign this year.”

Bystrom notes that Ron Paul’s ads have been on the air since this summer and most have had the production values of one of those movie trailer you see in the theater about “coming attractions”.

“In addition to being edgy, they’ve really placed him, I think, at the heart of this year’s political sentiment and that’s the ultimate outsider,” Bystrom said. “You know, he has some views that are even outside the Republican Party, but his ads really place him in that context.”

About 40 percent of the ads airing in Iowa over the past few weeks have been negative, attack ads — like a Ron Paul ad that accused Newt Gingrich of serial hypocrisy and focused on the $1.6 million consulting fee Gingrich received from Freddie Mac, the mortgage giant. Gingrich admits his campaign didn’t have a quick answer to that attack. Gingrich is low on campaign cash, so responding in kind hasn’t been an option. Gingrich has vowed to run only positive ads.

“It’ll be interesting to see whether, in fact, the people of Iowa decide that they don’t like the people who run negative ads,” Gingrich said in Atlantic, Iowa, on Saturday, “because you could send a tremendous to the country that the era of nasty and negative 30-second campaigns is over.” 

Texas Governor Rick Perry has spent $4 million on ads here. His latest smacks rival Rick Santorum.  Perry’s ads are reaching some voters, like Tim and Moira Crooks of Boone who went to see Perry in person on Saturday.

“We’ve seen his ads and we really enjoyed his last two debate performances and we’ve been undecided for a while because we were both Palin supporters and hoping that she was going to get in, so now we’re looking to see who we’re going to support,” Moira Crooks said.

Her husband, Tim, said of Perry: “I think he has the guts to stand up and start going what’s right and we need a leader that’s going to be able to step in and say, ‘This stuff’s wrong.'” 

The Des Moines Register “Iowa Poll” released this weekend showed Mitt Romney at 24 percent; Paul at 22 and Rick Santorum at 15 percent, followed by Gingrich as 12, Perry at 11 and Bachmann with 7 percent support.

(Check back Monday to hear Henderson’s Campaign Countdown report which includes all the information above, plus some snippets from the season’s campaign ads.)