Larry Sabato notes that in 2010 Republicans “probably threw away three seats when they nominated weak candidates in Colorado, Delaware and Nevada. Then, in the just-concluded election, they threw away, at a minimum, two more seats in Indiana and Missouri… So instead of having a tied Senate, or a tiny majority for one side or the other, Republicans are in the unenviable position of needing to levitate out of a deep hole they’ve dug for themselves.”
Despite a favorable Senate map in 2014 — Republicans only have to defend 13 seat while Democrats have to defend 20 — he concludes Republicans “will need a national wave, along the lines of what they had in November 2010… For a net six close races to tip to the GOP in two years, it will take more than good candidates and favorable geography; the atmospherics of 2014 will have to be clearly Republican.”