Senator John Ensign of Nevada, a conservative Republican with evident presidential ambitions, abruptly announced he carried on an extramarital affair for much of last year with a woman on his campaign staff, a confession that jarred his scandal-weary state as well as his party.
"It is the worst thing I have ever done in my life," Ensign said Tuesday in a brief appearance before reporters. He provided few details other than to say he does not intend to resign from Congress, and he did not disclose what prompted his decision to declare his infidelity. "If there was ever anything in my life that I could take back, this would be it," he added.
Ensign, 51, belongs to the men's group Promise Keepers, a Christian ministry. A member of the Senate Republican leadership, he was chairman of the party's campaign committee leading up to the 2008 elections in which Republicans lost eight seats to Democrats.
His announcement drew no public reaction from Sen. Mitch McConnell of Kentucky, the party's leader in the Senate, or other members of the leadership.
Ensign's spokesman, Tory Mazzola, said the affair took place between December 2007 and August 2008 with a campaign staffer who was married to an employee in Ensign's Senate office.
The woman worked at Ensign for Senate and Ensign's Battle Born Political Action Committee from December 2006 to May 2008. She also was married to a staff member in Ensign's Senate office. Neither has worked for the senator since May 2008, Mazzola said.
Ensign told reporters he would not disclose the name of the campaign aide involved in the affair. He described the woman and her husband as good friends.
"Our families were close," Ensign said. "That closeness put me into situations which led to my inappropriate behavior. We caused deep pain to both families and for that I am sorry."
Ensign's wife, Darlene, did not appear with her husband Tuesday, but she also released a statement about the affair.
"Since we found out last year we have worked through the situation and we have come to a reconciliation," she said. "This has been difficult on both families. With the help of our family and close friends our marriage has become stronger."
The Ensigns have three children.
The senator skipped the day's Senate session, missing a vote on legislation relating to the travel industry, an important part of his state's economy. He was not expected to return to the Capitol until at least Thursday.
In 2002, Ensign missed several public appearances and dropped all official business for about two weeks to deal with what his aides then described as a family matter. A person familiar with that episode, speaking on condition of anonymity because of the sensitivity of the matter, said Tuesday the absence followed an earlier affair.
Ensign was elected to the House in the Republican landslide of 1994 and won his Senate seat in 2000 after losing in his first try to Sen. Harry Reid, then a rank-and-file senator, now the majority leader.
At home, Ensign's admission comes on top of a string of disclosures and allegations about Republican Gov. Jim Gibbons. Since his election in 2006, Gibbons has been accused of sexual assault, sending love notes on a state phone and improperly firing a state employee. In recent court documents related to divorce proceedings, his wife, Dawn, accused him of a history of infidelity.
Within the Senate, Ensign's admission of an affair placed him in a lengthening line of Republicans to grapple with such issues. Sen. Larry Craig of Idaho retired at the end of his term last year, several months after pleading guilty in connection with charges resulting from an airport bathroom sex sting operation.
Last summer, Republican Sen. David Vitter of Louisiana apologized for a "very serious sin in my past" after it was disclosed that his Washington phone number was among those called several years ago by a Washington-area escort service that prosecutors have said was a front for prostitution.
Ensign was first elected to the Senate in 2000 and quickly rose through the Republican ranks. Last year, he was named chairman of the Republican Policy Committee, the No. 4 position in the party's Senate leadership. The committee coordinates the party's legislative efforts in the Senate.
Last month, Ensign traveled to Iowa for a speech organized by a conservative advocacy group, sparking speculation that he had an interest in possibly running for president. Aides said the visit was about staking out a leadership position within the Republican Party. Iowa is traditionally the first state to hold a contest in the presidential nominating season.
Ensign has been a rising star among conservatives, speaking out against President Barack Obama's stimulus package, statehood for the District of Columbia and union-organizing legislation and in favor of gun owners' rights.
Republicans lost eight seats last November under Ensign's campaign leadership, with one race, in Minnesota, still undecided. The losses put Democrats within one seat of having a 60-40 majority, enough to prevent the Republicans from blocking bills and appointments if all of them vote together.
Ensign is a veterinarian and adopted son of a Nevada casino mogul.