Matthew Yglesias thinks left-wing commentators spend too much time thinking and talking about the policy initiatives that have been proposed by the various Democratic candidates. With the filibuster and the Roberts Court in place, they have no realistic future. The key questions for the electorate, according to Yglesias, actually revolve around foreign policy and bureaucratic appointments, because those are the areas in which a Democratic president would have the most authority and discretion.
That is the voice of a true realo, and every word of it makes sense. If you accept it, the most appropriate nominee would be Biden, who has the most foreign policy experience and the biggest network of qualified potential appointees. If you prefer a more revolutionary approach, then the best choice would be Warren, who knows the bureaucracy inside and out, even if her ideas about foreign policy are unformed at best. For some reason, however, Yglesias undercuts his own message by maintaining that the Democrats need a fresh new spokesperson, not a retread. There is undoubtedly a case for that on electability, but not on qualifications.