That didn't stop Kerry from being nominated...
Kerry and Edwards were both do-nothings in Congress. "Do nothing" must be the new Dim Presidential qualification standard. All the Dim do-somethings did something stupid.
Obama would not add one single vote to the Democratic ticket in 2008.
After all, anyone who would vote for Obama in 2008 is already voting Democrat, 100-percent if not more, considering the power structure in Chicago and Illinois.
In fact, I see an Obama VP nomination as beneficial to the Republicans as thousands of moderate sensible Democrats would more likely flee to the GOP rather than see their party openly turned into a race-fest.