Nevada Sen. John Ensign announces resignation

LAS VEGAS — Nevada Sen. John Ensign announced he will resign amid an ethics investigation.

AP Photo/Las Vegas Review-Journal, Jessica Ebelhar

U.S. Sen. John Ensign, R-Nev., gives his final address to the Nevada Legislature as a sitting U.S. senator during a floor session at the State Legislative Building in Carson City, Nev. on March 22, 2011.

Ensign said Thursday he will send Vice President Joe Biden a letter Friday making the resignation official. He said he has not violated any laws or rules, but said he could no longer subject his family, friends and constituents to further investigations.

The Republican, who is under investigation by the Senate Ethics Committee, announced in March that he would not pursue re-election.

The 52-year-old 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.