The already tense campaign between Minneapolis U.S. Rep. Keith Ellison and Republican challenger Chris Fields came to a head during a contentious debate on KFAI radio Thursday morning, one marked by personal attacks and accusations of lying.

At one point, Fields accused Ellison of digging up and distributing information on Fields’ personal life, specifically a restraining order filed by Fields’ then-wife in 2006 (the state DFL Party took credit for distributing the information).

Ellison called Fields “really stupid” for bringing the issue into the debate. When Fields brought up Ellison’s history of child support payments, Ellison repeatedly called him a “scumbag.”

 “You’re a scumbag. You are a lowlife scumbag,” he said. “You are a gutter dweller.”

The debate was downright nasty throughout — Ellison repeatedly accused Fields of “lying all the time” about everything from whether he served on the House Foreign Affairs Committee (he has in the past) to Fields’ position on the GOP budget plan. Fields brought up Ellison’s recent divorce, and when he returned the restraining order issue, Ellison said, “my daughter is in the next room … I’m using a lot of self-control right now, sir.”’

 At one point, the moderator went to a commercial, only to have the microphones pick up the candidates arguing in the background when the show returned.

The full debate is posted online here.

In an interview after the debate, Fields said Ellison should accept responsibly for the opposition research because he’s given money to the state party. He said Ellison’s statement is indicative of his overall temperament.

“This is a guy who cannot work with people on the other side of the aisle,” he said. “Calling me a lying scumbag? Seriously? The issue is, there is my divorce, and there is his divorce. I don’t want to talk about anyone’s divorce, and I don’t think he does either.”

Ellison released a statement after the debate: “In response to my opponent’s false statement, I made an uncivil reference to him. I should not have done so. I acted beneath my personal standard as a public official, and I apologize. … His untrue reference to the terms of my divorce was over the line, but my comment to him was over the line too. His tactics are no excuse for my departure from civility. I will not allow this to happen again, and I regret my action.”

Fields said he and Ellison discussed the matter after the debate and agreed not to bring up their personal lives in the future. The two are scheduled to debate again at the Minneapolis Urban League next week.

Devin Henry can be reached at dhenry@minnpost.com. Follow him on Twitter: @dhenry