The Nevada Republican, who has been embattled since revealing he had an affair with the wife of a former aide, was facing a possible primary challenge from Rep. Dean Heller (R). Heller is now expected to run for the open Senate seat.
Ensign was facing growing pressure to exit the Senate race, and he has mounting legal bills related to his admission of the extramarital affair. He is the eighth Senator and third Republican to announce retirement this Congress. To see who else is leaving, check out our Casualty List.
Roll Call Politics currently rates the Nevada Senate race as a Tossup.
United We Dream protesters carry a mock coffin to the office of Sen. Ted Cruz, R-Texas, in the Dirksen Senate Office Building on Monday, July 21, 2014, to hold one of their "funeral services for the Republican Party" due to GOP positions on immigration. The immigration reform group visited several other Senate Republican offices to hold similar funeral services.