If somehow Hilary doesn't get the nomination I bet the Dem power brokers will try to sneak Biden in (which Biden is probably praying for). I can't imagine Bernie Sanders winning a national election.
What will be really interesting to see will be if Sanders and Trump win the nominations and Bloomberg runs 3rd party.
If that happens, he won't be the only one running off ticket. It's a free for all then.
Assuming it's not Hillary. Will it be Sanders?