The latest guest-blogger at Talking Points Memo is Ruy Teixeira, who is one of the people I link most frequently. Ruy follows and understands polls as much and as well as anyone out there, so I trust his judgment when he says this:
Who would help the ticket the most? Again, I agree with John [Judis] that [John] Edwards would likely help the most. I believe he would make a substantial contribution to increasing the ticket’s appeal among white working voters in culturally conservative swing states, especially where it is most necessary–outside of the unionized working class. Even if one assumes that Gephardt has appeal to the unionized rank-and-file of the working class, as opposed to labor leaders, that still leaves out the vast majority of the white working class–well over four-fifths. And it is among these non-unionized white working class voters that Democrats have had the most trouble and where Gore got really hammered in 2000.
The scuttlebutt is that Kerry is reluctant to pick Edwards because he they don’t get along particularly well. Well, suck it up. After 20+ years in politics, Kerry should have plenty of practice overlooking personal likes and dislikes in order to get the job done. The job in this case is to beat Bush and restore some sanity and cost-benefit analysis to policy formulation, not to have someone to “drink beer and shoot pool with” [Ruy’s words]. Gephardt brings Missouri; Edwards brings a more diffuse benefit, but given the number of swing states (around 15), spreading a 5% gain over 10 states is probably much better than concentrating it in one.
UPDATE: A Mason-Dixon poll in May found that
Without Edwards on the ticket, the poll said, Bush would defeat Kerry 48 percent to 41 percent. Three percent of North Carolina voters polled said they would back independent candidate Ralph Nader and 8 percent said they were undecided. But the race would be statistical dead heat — 46 percent to 45 percent — if Kerry and Edwards ran together, according to the poll.
The poll predates a wide array of bad news for Bush, so Kerry/Edwards might be even stronger now. Since Missouri has 11 electoral votes and North Carolina 15, even if it cost Kerry Missouri but won North Carolina, Kerry would come out four votes ahead on the deal. Moreover, Kerry/Edwards would still be competitive in Missouri; Kerry/Gephardt would not be competitive in North Carolina.