So, why the change in their confidence level? Mostly Obama's approval problems, as Stu explains: "With the president looking weaker and the news getting worse, Democratic candidates in difficult and competitive districts are likely to have a truly burdensome albatross around their necks."
The bullishness of Stu and Charlie is at somewhat at odds with the predictions being made by the various election models.
As of this morning, WaPo's Election Lab model gave Republicans a 53 percent chance of winning the Senate, which is down from a better than 80 percent chance a few months ago. The Upshot's LEO model gives Republicans a 61 percent chance of taking Senate control; Nate Silver's FiveThirtyEight model is the most optimistic about Republican chances -- giving the GOP nearly a 64 percent chance of winning the six seats they need.
In sum, everyone -- from the political handicappers to the political modelers -- see a Republican Senate as more likely than not. At issue is the magnitude of Republicans gains. Do Republicans squeak into the majority by a single seat -- as the Election Lab model suggests? Or do they surge into the majority with upwards of an eight (or even higher) seat gain as suggested by Rothenberg?
That's not just an academic question. Remember that the 2016 Senate class tilts heavily in favor of Democratic opportunities -- Illinois, Wisconsin, Pennsylvania, New Hampshire and Ohio are all Obama states currently held by a Republican senator -- which means that if the GOP wants to hold the Senate beyond the next two years, they need to win in the neighborhood of eight seats on Nov. 4.
Stu and Charlie see the possibility of 2014 being that good a year for Congressional Republicans. And that's a change that will make Republicans' day.