There's been much talk about a Rosenberg/Dean co-chair for DNC, with Simon Rosenberg being the behind the scenes organizer and Howard Dean being the before-the-cameras spokesman. There are good arguments for this, not the least being that Rosenberg is less likely to antagonize the establishment Dems while Dean has more of the public street cred needed to sell the party message.
But I am concerned that such an arrangement would lead struggle between Dean and Rosenberg over just who really is in charge. I understand that the two like each other, but that won't count for much if they start stepping on each others toes or can't work out a mechanism for shared power that will benefit everyone.
I think it would be best for the Dems if they had one person at the top. Whoever that person is has to have the power to do some housecleaning and a split chair might prevent that from happening. That may be the reason this idea is being proposed. A lot of establishment Dems fear that a Dean chairmanship would lead to their losing their position within the party power structure. They may be pushing this split-chair idea out of a simple desire to protect their turf.
When the idea of Dean for DNC chair first came up, I said that Dean should not accept the position unless he is granted the real authority to make real changes. I still hold to that position and thus would recommend against him joining in a power-sharing agreement of this sort. Rosenberg would be a good person to have on board to help Dean re-organize the Democrats. But it should be Dean who holds the ultimate position of authority.