I don't think it will happen until fall, 2016 and there will be one of each.
My sister and her husband have lived in Vermont for 35 years. I cannot tell you in what esteem Bernie Sanders is thought of up there.
He may not have a ghost of a chance to get the nomination.............but that does not make him a tiny bit less qualified to lead this great nation . I am getting tired of the dynasties............the Busch/Clinton families passing the Executive Position back and forth between themselves.
Time for some real fresh faces and new thinking.
I don't think it's realistic if only because there are like 19 projected R candidates.
If Sanders issues an invitation all 19 do not have to RSVP yes. A few looking for maximum exposure might take him up on it.
I could imagine "The Donald" going for it.
Bernie Sanders wants debates including both Democrats and Republicans. What do people think?