Hillary Clinton recently released her new book, titled What Happened, mainly aimed at explaining her experiences on the 2016 campaign trail. Indeed, President Trump’s victory was startling, as was Senator Bernie Sanders’ insurgent campaign’s successes. Hillary Clinton, a seasoned and well-known politician, was thrown into a tight and close primary and general election, by Sanders and Trump, two seemingly unknown and inexperienced politicians, respectively. So, what really happened?
Clinton happened. Hillary and her staff ran a non-policy based campaign that disenfranchised progressives through her flip-flops, and pick of Vice President. Her policies that she ran her primary on were a neo-liberal joke, and her record was a corporate monstrosity. Whatever failures she had were entirely of her own accord, not of the left, or Bernie Sanders, and if Democrats want to win again, they’ll have to learn lessons from her loss.
Clinton’s problems started far before the campaign had even begun. While beloved by many conservative democrats, many on the left disliked her as a corporate, and a sell-out, and rightly so. As pointed out by many progressives:
1). Hillary has taken millions from the financial industry, which as, then Professor, Elizabeth Warren noted in an interview about the “bankruptcy bill” on the Bill Moyer’s show, “She has taken money from the groups, and more to the point, she worries about them as a constituency.” 
Clinton opposed the bill as first lady, but after taking hundreds of thousands from the financial industry, she supported it as Senator. Clinton’s top three donors to her 2000 Senate campaign were from Real estate and Finance, and each donated roughly 100K. 
2). Hillary Clinton supported TPP and NAFTA, but as she entered the campaign, due to negative views of the two Trade Deals, she flip-flopped and claimed she opposed them. 
3). Hillary Clinton took millions from the Finance industry.  She had a record of voting for and supporting the financial industry, most notably with the $16 Trillion 2008 Wall Street bailout. [
Then, during the democratic party primary season, Bernie ran a grassroots, for-the-people campaign that focused on bringing young people to rallies and other events, across the country. From the beginning to the end, Sanders consistently drew large crowds and filled up venues.
In Iowa, Sanders spoke to over 70,000 people in his events—he received around 85,000 votes. Near the end of the campaign, in California, in about a month Sanders spoke to an estimated 227,000+ people.
Contrast this with Clinton, who often ran expensive, $2,700-per-person fundraisers. This was perfectly captured by the AlterNet, which ran an article titled, “Bernie Sanders Speaks to 28,000 People in Portland, While Hillary Hosts $2,700-a-Head Fundraiser”. In addition, Clinton had a Super PAC, which, like her, took millions from big money interests.
Clinton’s refusal to run a grassroots campaign, and her pro-corporate attitude strongly hurt what little credibility she had as a progressive.
In particular, Clinton lost big in the rust belt, even though older, white, evangelical, GOP voters are a declining share of the vote. 
I suspect that her loss was due, not only to her failure to visit the rust belt, but her previous (and continuing) support of NAFTA, which was responsible for the decimation of American industry, and TPP. Her comments about “putting coal out of business”, although misquoted by Trump, didn’t help her either.
As Sanders showed, consistently, that he was honest and genuine about his support for issues such as $15/hr minimum wage, singlepayer healthcare, free college…etc, Clinton attempted to lie her way through the primaries. She claimed, “Oh that was my policy as well”, when it clearly wasn’t. She flip-flopped on many issues, and that didn’t ring well with many voters.
As Jordan Weissman of Slate Magazine admitted, even in his strongly pro-Clinton article, that “Clinton…tied herself in knots attempting to explain her position on [Fight for 15]…[this] contrasted rather poorly with Bernie Sanders’ easily understood position, which is that the U.S. should have a $15 minimum wage. Period.” 
Then she tried to win millennial votes by parroting out celebrities to attract young voters. But this didn’t work. You see, Bernie Sanders didn’t attract voters by being young and hip, or having celebrities on his side. He came far, even in a rigged primary, by speaking about the issues that affect people.
In short, Clinton ran an elitist, corporatist campaign that didn’t speak on the issues. She only won the primary due to the DNC blatantly rigging the primary.  As TDMS Research points out, exit polls overwhelmingly favored Sanders, while the vote favored Clinton, while no such discrepancy was found in Republican primary exit polls. 
But how does Sanders costing Clinton the election fit into all of this? It doesn’t. The simple fact is, Clinton lost the election because her campaign made fatal errors that cost them votes. Even if you take the undemocratic and dishonest position that, Sanders, honestly pointing out Clinton’s flaws contributed to her loss, it’s still Clinton’s fault that she created those flaws. Hillary blaming Sanders for her problems is like a serial killer blaming the police for their criminal record—simply ridiculous.
So, what should Democrats do for 2020?
They’ll have to run progressive candidates. As polls showed throughout the election, Bernie Sanders did far better than Clinton against Trump. Sanders would have beat Trump, Cruz, and Kasich by 10.4, 14, and 3.3% respectively. Compare this to Clinton, who would have beat Trump by just 3.2%, Cruz by 5.4%, and would have lost to Kasich by 7.4% (RCP average). 
Even today, against Donald Trump, polls show that it’s progressives such as Sanders that do best. Of the candidates who might run in 2020, Sanders and Biden defeat Trump 54-39, and 52-39, respectively. While Biden certainly isn’t as progressive as Sanders, he’s a much more consistent leftist than Clinton. Cory Booker and Kamala Harris, the two most centrist candidates on the list, only manage 45-40 and 41-40 wins, respectively. 
In addition, it seems likely to me that the so-far relatively unknown Harris and Booker would attract more and more name recognition as the campaign goes on, opening them to lines of attack from the left and the right. For example:
1). Kamala Harris failed to prosecute now-treasury-secretary Steven Mnuchin’s One West Bank, even after clear violation of foreclosure laws. 
2). In return, Mnuchin made her the only 2016 Democratic Senator to receive cash from him.
3). While California Attorney General, her lawyers argued against early release of inmates, because it would drain prison labor pools. 
4). And more 
What about Booker?
1). Cory Booker has taken millions from the financial industry 
2). Cory Booker shut down a pharmaceutical importation act that would have allowed Americans to get cheaper drugs. 
3). And more 
The fact is, given neoliberals’ terrible records and painfully obvious attempts to pander to both sides, they’ll be open to attacks, from, both sides. It seems to me, logical, that they would do much worse in an extended campaign, just like Hillary Clinton did in 2016.
But once again, the trend seems to (unfortunately) continue. While some Democrats seem to have shifted left on healthcare, the party as a whole is still rife with issues.
Kamala Harris, the most likely candidate to have support of Democratic Party leaders, is still cozying up to wall street.  Nancy Pelosi–House Democratic leader—hasn’t come on board with Singlepayer. While Chuck Schumer has expressed his opinion that it’s “on the table”, he hasn’t formally endorsed it, most of the party is still fixated on Russia-Gate.  Whether they will wake up, remains to be seen.
This is the interview, albeit from a separate channel.
 SANDERS, BERNIE. OUR REVOLUTION: a Future to Believe In. ST MARTIN’S PRESS, 2018.
(On page 171)