U.S. Sen John Ensign, R-Nev., accompanied by his wife Darlene and son Trevor, announces he will not be a candidate for re-election, during a news conference in Las Vegas on Monday, March 7, 2011. (AP Photo/Oskar Garcia)
LAS VEGAS - Republican Sen. John Ensign of Nevada, damaged politically and facing a Senate ethics investigation over an extramarital affair, said Monday he won't seek re-election next year.
His decision to retire could set off a free-for-all to fill the seat coveted by Democrats and become a key to what will be a significantly reconstituted U.S. Senate, where eight members have now said they won't run again.
More than a dozen family members and supporters flanked Ensign during his brief announcement. His wife Darlene Ensign stood next to him, reassuringly patting his back at moments.
Ensign, 52, said he had fully intended to run until last week.
"I just came to the conclusion that I just couldn't put my family though it," he said.
In recent months, Ensign had been adamant that he would seek re-election. He said Monday it was difficult to give up the job he loved, but "I have learned through the mistakes I have made that there are consequences to sin."
Elected to the House in 1994, the former veterinarian preached family values, Christian fellowship and fiscal responsibility during his years in office.
Ensign acknowledged in June 2009 that he had an extramarital affair with Cynthia Hampton, a former member of his campaign staff, and that he had helped her husband, Doug Hampton, a member of his congressional staff, obtain lobbying work with a Nevada company.
Ensign, however, insisted the investigation by the Senate Ethics Committee didn't affect his decision to retire, and he again denied he broke the law or ethics rules.
"It had zero effect," the senator said. "If I was concerned about that, I would resign. That would make the most sense, because then it would go away."
Ensign also acknowledged in recent months that he was prepared for a tough election campaign, in which he was expected to face Rep. Dean Heller or Lt. Gov. Brian Krolicki in the GOP primary.
He also could have faced an equally brutal general election fight. A roster of popular Democrats including Rep. Shelley Berkley of Las Vegas, Secretary of State Ross Miller and Attorney General Catherine Cortez Masto were named by party leaders as prospective rivals.
Some observers wondered if Sharon Angle, a tea party Republican who lost a Senate bid to incumbent Democrat Harry Reid in November, might take another shot at going to Washington.
A call to Angle to ask if she would seek the open seat was not immediately returned.
In a Twitter message about Ensign, she said, "Nevadans are thankful for his service, and I wish him well."
With Ensign's exit, Heller, Nevada's former secretary of state, could emerge as the front-runner, Duffy said.
"He held statewide office for 12 years," she said. "Unlike many members of Congress, he is pretty well known statewide."
Heller said in a prepared statement that he and his wife wished Ensign the best. "This must have been a very difficult decision for John to make," the statement said.
Heller did not return a phone call Monday seeking comment on a possible run for Senate. Krolicki said he and his family were considering their options.
Berkley said Ensign's announcement was not unexpected.
"I am not surprised," she said. "I think John could have gone either way."
Berkley said the announcement will likely allow Republicans to rally around a front-runner and avoid a nasty primary. She said she is still weighing her options about a possible run.
"I am taking my time with this decision," Berkley said.
Ensign's announcement did not dampen criticism from the watchdog group Citizens for Responsibility and Ethics in Washington. The organization called for the Senate Ethics Committee to continue its investigation and not use the announcement as a reason to drop it.
"Unless and until Sen. Ensign resigns, the investigation should proceed full-steam ahead," said Melanie Sloan, the group's executive director.
Once elected with 55 percent of the vote, Ensign's admission that he cheated on his wife seemingly marked the beginning of his political downfall.
In just two terms, he had gained a foothold in the GOP's Senate leadership and had been discussed as a potential presidential candidate.
"If there was ever anything that I could take back in my life, this would be it," Ensign said at the time. "I violated the vows of my marriage."
The Justice Department and the Federal Election Commission investigated then dropped the cases with little explanation.
The Senate ethics panel, however, recently named a special counsel to look into the matter.
