The one thing that the polls do show, though, is that John Edwards is a devastatingly effective VP choice for Obama. He performs equal or better than the other Democrats in their home states and helps Obama beat McCain's VP picks in their home states.
Take Pennsylvania, where Ed Rendell is a popular governor. But against any Republican pairing, an Obama/Edwards ticket does better than Obama/Rendell by 3 to 5 points, and leaves every other pairing far behind. There's no reason to consider Rendell for VP against numbers like this -- John Edwards can beat him in the state he's supposed to secure.
Or take Kansas, where Kathleen Sebelius is popular. An Obama/Edwards ticket does better than Obama/Sebelius against two opponents, while Obama/Sebelius does better than Obama/Edwards against two. There still is good reason to consider Sebelius, in part because her history of converting Republicans would reinforce Obama's message of national unity (which I find annoying, but whatever). But it's pretty impressive that Edwards is neck-and-neck with her on her home turf.
The only Obama VP possibility who does better than Edwards in his home state is Republican Senator Chuck Hagel, who could win Nebraska for Obama. This isn't too surprising -- picking a GOP Senator who won his last re-election with 83% of the vote will score with crossover voters. (BTW: This does not actually mean you should support Hagel, who is so insane on social issues that he votes against funding to reduce teen pregnancy with education and contraceptives.) And Edwards could actually steal an electoral vote or two under Nebraska's unusual district-based system.
How about when we look at McCain's Republican VP choices in their home states? Well, Edwards cleans up against Minnesota GOP governor Tim Pawlenty. While SurveyUSA has Obama beating McCain by 5 in Minnesota, Obama/Edwards beats McCain/Pawlenty by 7. Now consider that Pawlenty adds 10-13 points to McCain's total against any other Democratic VP, creating a 5-8 point McCain win. The Republican governor is strong in his home state, but the Carolina mill worker's son is even stronger.
Mitt Romney is strong in Michigan, where his father was governor. His presence on the ticket inflates McCain's 4-point lead to as much as 19! But against Edwards, that lead drops to 3.
I think there's upside even to these strong numbers. The economy is going into recession, and economic issues are even bigger than the war in most voters' minds. According to the latest polling, 88% of voters regard the economy as a 'Very Important' issue, more than anything else. (There's a 3-way tie at 78%, between education, jobs, and health care.)
We should have confidence in Barack Obama's foreight on Iraq to stand at the core of an appealing foreign policy message. Economic issues are among McCain's least-known vulnerabilities (take a look at his voting record on the minimum wage) and we need a VP who can swing the hammer of economic populism until he breaks. Nobody does that better than John Edwards.