In the Obama-Clinton primary of 2008 things became just as testy and ugly between Hillary and Barack as they are now between Hillary and Bernie. Bill Clinton even said 'do you really think America is going to elect a black guy?'
AND YET! When the general election began Hillary and Bill campaigned hard for Barack Obama and he in turn made her the 2nd most powerful person in the US government, Secretary of State.
Bernie Sanders will campaign hard for Hillary in the general!