UN-ELECTABLE? That's just corporate-speak for "can't be bought!" ~ Bernie Sanders is absolutely electable. Donald Trump is unelectable. Ben Carson is unelectable. So are Ted Cruz and Mike Huckabee, plus quite a few more.
In the Hillary Clinton was a Republican "Goldwater Girl" who campaigned to help overturn the Civil Rights Act and re-segretate the country. Bernie Sanders marched with Martin Luther King, Jr., and worked to de-segregate student housing in Chicago.