Well, Joe is wrong, because the policies are popular, and that's what Nate Silver's tweet is about. Although I agree, branding isn't quite the right word when comes to how Americans feel about socialism, because the Democrats don't really own the product of socialism, but, I think for obvious reasons (the cold war, McCarthistic tendencies) socialism has been something of a dirty word in our culture. (For my part, Joe Lieberman is exactly the kind of establishment democrat that the party should leave behind.) Although if the Democrats want to embrace these policies, they either need to find a more palatable way of characterizing those policies or change how Americans think of socialism, which perhaps can be done through something like branding. Democrats should realize however, that whatever policy they adopt, they will be labeled socialists and crazy lefties by the right, no matter how reasonable they are.