I hadn't known that Jim Webb has what the Washington Examiner calls a "near-total opposition" to the death penalty. (A spokeswoman says he opposes it in all but "significantly severe cases," though it's not clear what that means.)
My first reflex is to call that problematic for Webb's prospects on an Obama ticket--especially if Webb's role would be wooing working-class whites. But then, death penalty politics have changed over the past decade, thanks to a drop in crime and a rise of DNA-evidence acquittals, so who knows. But if Obama should be concerned about it, the Examiner also notes that Virginian Democrats and potential Obama veep picks Tim Kaine and Mark Warner are to the right of Webb of the issue.
P.S. See here for discussion of Webb's potential problem with women, an especially touchy issue in the context of Hillary's defeat.