By Timothy Pratt
LAS VEGAS (Reuters) - Senator John Ensign, a two-term Republican from Nevada who admitted having an extramarital affair with a staff member, announced on Monday that he would not seek reelection in 2012.
Ensign, who is facing a Senate ethics committee probe stemming from the affair, apologized but said it had "zero effect" on his decision to retire.
"As I have learned through my mistake, there are consequences to sin. When a person is in a leadership role, those consequences can affect a lot of people in a very negative way," Ensign said at a press conference in Las Vegas.
"I do not want to put my family, those that I care about, or this state through what would be a very ugly campaign that would ultimately cause a great deal more pain than has already been felt as a result of my actions," he said.
Ensign, 52, has admitted to having an extramarital affair in 2008 with Cynthia Hampton, who worked for his campaign, and whose husband, Doug, was a legislative aide to the senator.
The ethics investigation focuses in part on some $96,000 Ensign's parents gave to the Hamptons, which Ensign's attorney has characterized as a gift.
"He finally saw the light that everyone has seen for a long time. He was deluded thinking he could win the race," Nevada political columnist Jon Ralston said, adding that Ensign stepping aside was good news for Republicans.
"Dean Heller is the favorite and the Democrats haven't announced a candidate yet," he said, referring to Republican Dean Heller. "Now the national Republican party will want Heller to get into the campaign as fast as possible."
Sherry Bebitch Jeffe, a University of Southern California political analyst, said Ensign's departure could create an opening for Democrats.
"If there's a candidate, a strong candidate for the Democrats, I'd say they certainly do have a chance," she said.
Senator John Cornyn, chairman of the National Republican Senatorial Committee, said the election to replace Ensign would be a choice "between a Republican candidate who believes in smaller government, fiscal responsibility and creating good, private sector jobs, and a Democrat candidate who believes in keeping our country on the same reckless fiscal path of more government and higher taxes."
"Republicans welcome this choice and I am confident we will successfully retain this seat as we work to win back a new Senate Republican majority," Cornyn said.
Ensign is the third Senate Republican to decide not to seek reelection, following Assistant Senate Republican Leader Jon Kyl of Arizona and Kay Bailey Hutchison of Texas.
Five members of the Senate Democratic caucus have said that they won't seek another term next year: Democrats Daniel Akaka of Hawaii, Jim Webb of Virginia, Kent Conrad of North Dakota, Jeff Bingaman of New Mexico and independent Joe Lieberman of Connecticut.
Senate Majority Leader Harry Reid of Nevada narrowly won reelection last year over a Tea Party-backed Republican candidate Sharron Angle. Reid's win was attributed in part to strong support from Nevada's growing Hispanic population.
(Writing by Dan Whitcomb, Editing by Greg McCune)