When Hillary withdrew Obama only had about 200 more ~pledged~ super delegates than she did, it was actually more or less the regular delegates that swung it in his favor. The states he won, he won by larger margins than Hillary did in many of her states, and he won many smaller states giving him more of an edge over Hillary. But Hillary withdrew before the DNC and released her supers to vote for Obama if they wanted to. Bernie's stated he's going to take it all the way, usually the supers will realign their votes with majority popular vote, with some leeway since they can still vote for whoever.