Sen. Ensign’s decision to retire probably makes it easier for Republicans to hold the Nevada seat next year. Ensign possibly would have faced a primary challenge–not necessarily from a more conservative candidate, but from a Republican who could have made a strong case about the importance of dumping a tarnished incumbent and putting forward a fresh face that can win. The post-Ensign GOP field may include Lt. Gov. Brian Krolicki, Rep. Dean Heller, and the three 2010 senatorial candidates: Sharron Angle, Sue Lowden, and Danny Tarkanian. The Democratic nominee could be Rep. Shelley Berkley and many Nevada Republicans think she’s potentially formidable.