“The sheepdog is a card the Democratic Party plays every presidential primary season when there's no White House Democrat running for re-election.”
Spoiler alert: we have seen the Bernie Sanders show before, and we know exactly how it ends. Bernie has zero likelihood of winning the Democratic nomination for president over Hillary Clinton. Bernie will lose, Hillary will win. When Bernie folds his tent in the summer of 2016, the money, the hopes and prayers, the year of activist zeal that folks put behind Bernie Sanders' either vanishes into thin air, or directly benefits the Hillary Clinton campaign.