Bernie Sanders will use his followers as a bargain chip when he meets Obama in the White House, but it will gain him nothing. He is toast, he lost, he is done. Time for him to put on his big boy pants and move on. This run to the white house is kaput. The sooner he, and his failed socialistic agenda, disappears the better off we all are.
I think it's highly likely that Bernie Sanders will "bargain" with President Obama when they meet in the White House - and Sanders' followers are part of that bargaining. Sanders is a wily campaigner, and he knows that his movement has enough leverage now for him to have a significant role within the Party, even if he doesn't clinch the nomination.
Bernie Sanders will almost certainly use his supporter as a bargaining chip for him and his socialist agenda. Berni Sanders knows the revolution he has started and wants to see it continue into the White House. He will try to sure up support for his programs and policies before agreeing to back Hillary Clinton.
Bernie needs to use whatever bargaining chips he has, and he is an intelligent man. He'll understand that the best way to move forward is to explain that he is at the head of a movement, like it or not. Where he goes from there is anyone's guess, but he should use his followers to get there.