"I think what you're saying is probably true to a degree," Jones said of the Republicans-are-shrinking theory, "but it can't explain everything, with that party gap."
For example, we are still left with the matter that Pew's polling director explained to me -- that the Dem approval rating for Obama is so amazingly high, creating much of the gap by itself. And Jones thinks that while the GOP shrinking would make some difference, it doesn't by itself explain numbers as low as this. The Gallup organization informed me that GOP self-identification in this poll was only 26%, compared to 34% in 2004, with Democrats holding steady at last year's figure of 36%. But the higher base of Democrats should just as easily create a more heterogenous party, with more dissenters.
"Both parties are more homogeneous, just the way they look at everything and the way the people go to Washington and vote, is pretty much following a straight party line," said Jones. "I suspect there's probably more animosity between people of different political views than in the past."
So is Obama creating the polarization, or was it already there from the long-run trends? "Basically, I think it's both," said Jones. "I think the trend is there, and I don't know how different it would be if he was doing things more palatable to Republicans." But again, Obama's policies obviously aren't too endearing to the pool of GOP respondents.
Interestingly, Rove acknowledged the trends early in his column, but then quickly moved on and continued with his main thesis.
Oh, and one other thing: The Gallup poll's memo says there's one other president who inspired an even greater approval gap between his own party and the opposition, of 83 points: George W. Bush, during 2004, compared to Obama's 63-point gap right now. Jones told me the gap was later decreased when Republican approval went down, too.
Late Update: This post originally referred to Jones as Gallup's poll director. His title has been corrected.