The general pattern there is the incumbent party messes things up and the challenger says they will fix it and gets elected. Then they mess things up more and the former incumbent party says they will fix it and gets elected. Then they mess it up worse and the former incumbent party says they will fix it...ad nauseum, until we are all nauseous.
That’s all true. But there are other factors at work too:
1) Turnout is much smaller than in presidential elections. Electorate will be smaller, older, whiter, more conservative, therefore more Republican than is generally the case in presidential elections.
2) Intensity and exhaustion tends to favor the party out of power. The opposition to the incumbent is intense, the bloom is off the rose for many of its initial supporters.
3) The Dems have the added burden of having to defend so many US Senate seats in red states easily carried by McCain and MR——states where BHO’s approval ratings are much lower than the national average.
The Dems are facing a perfect storm this year. Throw in Ebola and ISIS-—not to mention Panetta’s scathing critique...well...