The GOP presidential candidates are making their final cases on Iowa’s airwaves, and one ad man — Rex Elsass of the Strategy Group for Media — has worked for three of them.

Elsass’ central Ohio-based firm is doing the media work for former Speaker Newt Gingrich (Ga.). Earlier this year he shot ads for Rep. Michele Bachmann (Minn.), and in 2008, he was Texas Rep. Ron Paul’s media guy.

That might not be unheard of, but in this case the consultant has taken advantage of overlapping relationships with rival candidates. Gingrich has vowed not to run negative ads and has decried the super PACs that have incessantly attacked him through radio and television. But should he survive Iowa and forge ahead, Gingrich will likely have the money for a major ad blitz. And Elsass isn’t always known for staying positive.

In fact, Gingrich’s ad man has “a reputation for winning, no matter what it takes,” according to the Columbus Dispatch, which has long chronicled Elsass’ firm.

In the tiny world of political consulting, reputations and history have long life spans, especially when a firm does so much business.

“When you get into the race, he’s the first guy that contacts you,” one former client said.

Some of Elsass’ former clients and his competitors, unprompted, offered examples of his work that they considered, at the very least, to be poor form.

The most egregious, and one Elsass has previously said he regrets, came in 2007 when he found himself in the unusual position of having two former clients running against each other in a Republican Congressional primary.

Rep. Bob Latta faced Steve Buehrer in Ohio, and Elsass made an attack ad for Latta. The spot included Buehrer sticking out his tongue at the camera, an outtake from footage Elsass had captured at Buehrer’s home back when the man was a Strategy Group client.

“It potentially puts a chilling effect on every campaign in Ohio,” Buehrer told the Dispatch at the time. “How can you trust as you stand in front of a camera that the vendor you’re paying won’t turn around and sell that to your adversaries? As a lawyer, if I did that, I’d be disbarred.”

Consultants from across the country said Elsass’ name is still associated with the dust-up, even though he apologized.

“If I was Bachmann right now I’d be worried they’d use some of my B-roll,” one consultant said. “History shows that he’d use something against her.”

But Bachmann campaign manager Keith Nahigian told Roll Call that the Congresswoman was pleased with the work Elsass did for her and that some of it is likely to appear in her new campaign ads, which will be edited by another firm.

“He has always been really professional and does great work. We own all this great, great footage. You use a lot of vendors during a campaign,” said Nahigian, who himself rose from consultant to campaign manager when Ed Rollins quit working for Bachmann’s effort.

Do Elsass’ former clients have anything to worry about? “Of course not,” a Strategy Group for Media source told Roll Call.

Of course, borrowing ideas swings both ways.

Elsass made an ad for then-Senate candidate Rand Paul — son of the Congressman — showcasing the Kentucky Republican as willing to fight the “Washington Machine.” Sound familiar? Ron Paul’s newest ad in Iowa says the Congressman is the one man standing against the “Washington Machine.”

A 1994 incident also mars Elsass’ reputation. He had been serving as executive director of the Ohio Republican Party and left to work for Bernadine Healy’s Senate primary bid against then-Lt. Gov. Mike DeWine.

When voters received anti-DeWine mailers, the state party realized its donor list had been snatched. Two sources said Elsass settled with the party and that tension still lingers within the DeWine family. The Dispatch described it as “a scandal involving a list of campaign contributors that was stolen from the party,” and the Sentinel-Tribune said the primary was tainted “by the unauthorized sharing of a coveted Republican donor list.”

The Sentinel-Tribune also reported that Elsass “conceived the infamous 2000 ads against Ohio Supreme Court Justice Alice Robie Resnick,” earning the state “a reputation for some of the harshest campaigning in the nation.”

“Both the contributions behind and the content of the ads were found to be illegal by the Ohio Elections Commission,” according to the Sentinel-Tribune.

One Republican political consultant remembered Elsass pitching a candidate an ad, and then noticing he later made a remarkably similar spot for the candidate’s primary rival.

Another consultant said a client went to the trouble of writing a legalese-laced letter warning Elsass that his footage could never be used elsewhere.

“This is not a person who lacks skill,” said a Republican who is familiar with Elsass’ work and reputation. “The rap on this guy is that he … plays it over the line.”

Others recognized both his talent and his style.

Elsass has been known to ask his clients to bow their heads in prayer during official meetings. The Strategy Group source said employees “are encouraged to practice their faith openly.”

Elsass declined to be interviewed for this article, but the Strategy Group source pointed Roll Call to its nearly 40 “Pollie” awards for political ad work and noted that the Strategy Group in 2010 helped to elect more Republican Members of Congress than any other firm.

Among the prominent ads the Strategy Group created in 2010 were spots for Wisconsin Republican Sean Duffy, featuring the former “Real World” star swinging an ax and logrolling. Duffy won his race.