However, Biden's case is probably stronger than I indicated, because he tends to be most popular among voting groups with a lot of undecided voters, which means a lot of persuadables. In particular, Biden's strength with senior citizens could be a real asset. How so? Because seniors are far more likely to be undecided in this election than their younger counterparts.
Below, I have averaged the Gallup national tracker crosstabs by age over the course of the last three weeks. The only thing I am interested in is the number of voters who are not committed to either Obama or McCain (either truly undecided or claiming that they'll vote third-party). This is how that vote breaks down by age group:
18-29 9% undecided/otherSeniors are about 50 percent more likely than other voters to be uncommitted at this point in the race. Voters aged 65+ will eventually represent about 20 percent of the electorate, but they may represent more like 30 percent of the pool of persuadables.
30-49 9% undecided/other
50-64 10% undecided/other
65+ 16% undecided/other
Now, what did Joe Biden's favorables look like in that recent Rasumussen poll?
VF = Very FavorableThat is a pretty strong age-based correlation. The only figure that breaks the pattern is Biden's relatively strong performance among 18-29 year olds, but that is probably because that cohort is so overwhelmingly Democratic at the moment that they are likely to support any Democrat.
SF = Somewhat Favorable
SU = Somewhat Unfavorable
VU = Very Unfavorable
Age VF + SF = Favorable SU + VU = Unfavorable
18-29 3 + 26 = 29 14 + 8 = 22 (+7)
30-39 4 + 19 = 23 17 + 16 = 33 (-10)
40-49 8 + 19 = 27 22 + 18 = 30 (-3)
50-64 19 + 24 = 43 19 + 18 = 37 (+6)
65+ 21 + 24 = 45 12 + 21 = 35 (+10)
Biden's net favorable score among seniors was the highest of any Democrat that Rasmussen tested, except for John Edwards, who has since disqualified himself:
Edwards +21What a Biden pick really would be is a redux of Gore-Lieberman. Al Gore got quite a large bounce in Florida when he selected Lieberman, and if Obama were to pick Biden, he is probably committed to playing Florida out to the end, or at least until the last 15 days of the campaign.
By the way -- I wouldn't read too much into Biden's "I'm not the guy" statement because his demeanor seemed to be pretty sarcastic and jocular. Then again, assuming it was an unplanned joke, his statement couldn't have gone over too well with the Obama campaign. Hell, if they were really evil, they could have told all the candidates they weren't the one and then saw who leaked or broke their game face.
In any event, based on my 99.99% uninformed aggregation of information and intuition, I'd probably place the candidates into something like the following tiers:
1. Biden, Kaine
2. Sebelius, Clinton
3. Bayh, Reed, Other