Wisconsin GOP Senate candidate Tommy Thompson spoke out about his son's recent birther joke directed at President Barack Obama, telling reporters on Tuesday that he does not believe his son needs to apologize publicly or to the president.

"He has already apologized, and that's enough," said Thompson at a press conference in Milwaukee after receiving the endorsement of the U.S. Chamber of Commerce.

At an event hosted by the Kenosha Republican Party on Sunday, Jason Thompson joked, "We have the opportunity to send President Obama back to Chicago -- or Kenya."

Thompson also played down his son's role in the episode, insisting to reporters on Tuesday that his son was simply repeating a remark made by an audience member.

"It was an offhanded remark that somebody mentioned in the audience," said Thompson, according to WisPolitics. "If you look at the movie, he didn't say it. Somebody in the audience said it and he repeated it, and I've talked to him about it and he apologized and that's it."

The video -- which was first posted by BuzzFeed and recorded by a Democratic tracker -- does indeed show Jason Thompson making the joke. An audience member can be heard faintly making a comment just before Thompson makes the Kenya remark.

Thompson also said his son feels "terrible" and added that "nobody is suffering more than he is about this."

The former governor did not attend his son's event, although Republican National Committee Chairman Reince Priebus and Wisconsin Republican Party Chairman Brad Courtney were in attendance.

Thompson and his opponent, Rep. Tammy Baldwin (D-Wis.), will be meeting for their second of three debates against each other on Thursday in Wausau, Wis.

According to a HuffPost Pollster average of the polls in the race, Baldwin currently has about a 4 percentage point lead over Thompson.

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