The Clinton campaign and the Democratic establishment have been completely blindsided by a little known uncharismatic septuagenarian who is pretty much just repeating the talking points and ideas from moveon.org and thedailykos.com. These voters have no animosity towards Clinton and generally like her. Despite this (moderate) affection a large segment of mostly young voters want no part of what she's selling. Some feel that the Democrats have compromised too much with Republicans and got nothing out of it. Others feel Democrats have sold out to corporate interests and, let's face it, if any Democrat has done that it's the Clintons. She can try to run from the stigma that she made more in one speech to Goldman Sachs than they make in a year. Income inequality is a big concern of theirs and Hillary Clinton is one of those people who are rich. Very very rich. And she made it the wrong way, just talking in front of Wall Streeters. Still others just like what Bernie Sanders is selling. When Clinton tries to sell the same things it feels inauthentic and "me too."
Clinton has tried to push that Sanders can't win a general election. His supporters don't want to hear that. They believe that Sanders' policies would be good for 95% of America. At least 51% will realize that. In most recent polls, Sanders polls as well as she does against Republicans, if not better. Clinton has been selling pragmatism and dealing with the reality that Republicans control the House and Senate. The Sanders' supporters either don't want to accept that or don't care. Those that don't want to accept it are like Sanders. The first group believe that once voters here about Sanders' policies it will start a revolution and districts throughout the country will elect progressive candidates. The second group wants a progressive in the White House. So what if Republicans control everything else. At least they'll have someone fighting for progressive policies who won't cave the way President Obama has. And if Sanders is selling progressivism from the White House he'll win more hearts and minds.
So what if even Democratic economists say Sanders' economic plan doesn't add up. Sanders isn't about reality. He's about what they want government to be. And that's something Clinton can't sell.
Aside: My favorite part is that Sanders assumes the U.S. will save $324 billion a year on prescription drugs when we only spend $305 billion. Not only will the drug companies develop and sell the drugs for free but they'll pay us to take them from them.