Nevada Sen. John Ensign announced Thursday that he will resign amid an ethics investigation, insisting that he's done nothing wrong but saying he could no longer subject his family and constituents to further investigation.
Ensign said in a statement that he will send Vice President Biden a letter today making the resignation official.
"While I stand behind my firm belief that I have not violated any law, rule, or standard of conduct of the Senate, and I have fought to prove this publicly, I will not continue to subject my family, my constituents, or the Senate to any further rounds of investigation, depositions, drawn out proceedings, or especially public hearings," he said. "For my family and me, this continued personal cost is simply too great."
The Republican, who is under investigation by the Senate Ethics Committee, announced in March he would not pursue re-election.
Ensign, 52, 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 two Nevada companies.
Ensign's admission that he cheated on his wife seemingly foreshadowed his political downfall. Amid the scandal, his parents provided the Hamptons with $96,000 described as a gift, and Ensign helped find Doug Hampton a lobbying job.
The Justice Department and the Federal Election Commission investigated, then dropped the cases with little explanation. The Senate ethics panel, however, named a special counsel to look into the matter.