Senator John Ensign

Senator John Ensign (R-NV) announced this afternoon that he is resigning from the U.S. Senate effective May 3. Ensign admitted in June 2009 that he had an affair with Cynthia Hampton, the wife of one of his top campaign aides, and has since been under investigation for a number of possible criminal or ethics violations. The alleged violations each related directly to the affair, including $96,000 in payments to the Hampton family and conflicts of interest relating to Doug Hampton’s lobbying firm.

The Federal Bureau of Investigation and the Federal Election Commission both dropped their investigations in late-2010, but the Senate Committee on Ethics appointed a special council in January to continue its work. Ensign announced in March that he would not seek reelection in 2012 and suspended his campaign committee, but claimed that the scandal had no bearing on his decision. At the time he stated, “If I was concerned about [the ethics investigation], I would resign.”

States have the authority to set their own procedures for replacing a U.S. Senator who leaves office during his term. Under Nevada law, Governor Brian Sandoval (R-NV) will have the authority to appoint a replacement to serve out the remainder of Ensign’s term. Some are already speculating that Sandoval will appoint Representative Dean Heller (R-NV 2nd), as Heller was already running to replace Ensign in the 2012 election. If Sandoval appoints Heller to the Senate, that would trigger a special election to fill Heller’s seat in the House of Representatives.

Update 4/27/2011: Governor Brian Sandoval (R-NV) has appointed Representative Dean Heller (R-NV 2nd) to fill Senator John Ensign’s (R-NV) seat in the U.S. Senate. There will be a special election to fill Heller’s seat in the U.S. House of Representative.