Rasmussen has long been an outlier in the Presidential approval polls, and I have been skeptical of them since last year. Still, it's believable that things are heading down for Obama and the Dems. Anyone know what their 'likely voter' model does, and if they still do landline robocalls-only? Both of these could affect their results.
Update. Here is an illustration of why I am skeptical of Rasmussen:
A new Rasmussen Reports national telephone survey finds that 37% of voters now favor her confirmation while 43% are opposed. (7/15) For the past 2 weeks, they have found more opposed than support.
link
Compare with other pollsters on substantially the same question:
Diageo/Hotline 50-28
Gallup 53-33
CBS 30-14
Quinnipiac 54-26
CNN 47-40
ABC/WashPost 62-25
http://www.pollingreport.com/court.htm
Sorry Beet, but the largest margin the Democrats have achieved over the Republicans in a Congressional election in a generation was 11 points (2008). If you believe the polls you cited (with the exception of ORC), then you're really out of touch with reality.
While Rasmussen may be slightly optimistic about the Republican vote (I put the Democrats up by 2 points at this time), polls showing the Democrats ahead by 16 - 37 points are laughable.
Oh, and to correct a couple of your polls, the most recent results of FD (you identify them as Diageo/Hotline) from July 9-15 is 39 Democrat and 32 Republican, a 7 point Democrat advantage, not the 22 points you cited, while the Quinnipiac survey from June 23-29 was 42 Democrat and 34 Republican, an 8 point Democrat advantage, not the 28 points you cited.