Former Nevada Sen. John Ensign, a Republican, declined to run for re-election after confessing to an affair with the wife of one of his top staffers in 2009. The affair was made public by the aide, Doug Hamilton. Ensign faced a Senate Ethics investigation until the end of his term in 2011, the results of which may yet lead to federal charges. At issue is the nearly $100,000 Ensign's parents paid Doug and Cynthia Hampton in alleged "hush money." Adding to the scandal was Ensign's position in Republican Senate leadership and his connection to prominent religious groups.