"If [when?] Hillary takes the Democratic nomination, [I said 'takes', not 'wins'] Bernie is not going to run a Green Party ticket. That would a tactical and strategic mistake.
Tactically it would almost certainly guarantee a Trump victory. Such would validate DNC accusations that he 'did a Nader'. If Hillary loses to Trump on her own, those accusations will be made anyway, but won't have the same kind of weight.
Strategically, Bernie has made serious investment in the Democratic Party. Even if Hillary wins, it will likely be a narrow victory. If she loses, Bernie is positioned to become the effective head of the party. Either way, he returns to the Senate far more powerful than he was before. In addition, he will be able to use the party's infrastructure to move the Brand New Congress project forward."
Tactically it would almost certainly guarantee a Trump victory. Such would validate DNC accusations that he 'did a Nader'. If Hillary loses to Trump on her own, those accusations will be made anyway, but won't have the same kind of weight.
Strategically, Bernie has made serious investment in the Democratic Party. Even if Hillary wins, it will likely be a narrow victory. If she loses, Bernie is positioned to become the effective head of the party. Either way, he returns to the Senate far more powerful than he was before. In addition, he will be able to use the party's infrastructure to move the Brand New Congress project forward."