LAS VEGAS (AP) — Sen. John Ensign, Nevada Republican, said Monday he won't seek re-election in 2012.
Mr. Ensign, who is under investigation by the Senate Ethics Committee, said he decided last week against seeking a third term because he was worried about the effects of a campaign on his family.
"I'm putting them first, instead of my career," Mr. Ensign said.
He acknowledged in June 2009 that he had an extramarital affair with a former member of his campaign staff and that he had helped her husband, a member of his congressional staff, obtain lobbying work with a Nevada company.
In recent months he was adamant that he would seek re-election and that he did nothing to violate the law or Senate ethics rules.
Mr. Ensign denied that the ethics investigation weighed in his decision. He denied again that he broke the law or ethics rules.
"It had zero effect," he said. "If I was concerned about that, I would resign. That would make the most sense, because then it would go away."
Democratic Senatorial Campaign Committee chief Guy Cecil promised a grass-roots effort to elect a Democrat.
"Whoever Republicans field as their candidate will have a tough time holding onto this seat in a blue-trending state with President Obama at the top of the ticket," Mr. Cecil said.