10. John Ensign « The Washington Independent
Sen. Ensign (R-Nev.) began 2009 with an increased national profile, stemming from his 2008 role as chairman of the GOP Senate party committee, and pundits speculated about a potential 2012 presidential bid. But a quick turn of events ended all that. On June 16, Ensign publicly acknowledged an affair with a former campaign aide and stepped down as chairman of the Republican Policy Committee. Despite calls for him to resign, Ensign remains in the Senate and is not up for reelection until 2012.