A new book takes a new look inside the 2016 election.
"Shattered: Inside Hillary Clinton's Doomed Campaign" paints the picture of a presidential bid plagued by missteps and missed opportunities, right from the start.
ABC News Chief National Correspondent Tom Llamas spoke with the authors, Jonathan Allen and Amie Parnes.
President Donald Trump winning the 2016 election was a headline that rocked the world and shocked many. But the news shouldn't have taken the Clinton campaign by surprise.
Just months before Election Day, a longtime Clinton adviser drafted a memo telling the campaign Trump could win and not to underestimate him in battleground states.
"This adviser says Donald Trump can win this election. 'Fact,' he says at the top of this memo. As the memo goes on, it says, 'I would add 3 or 4 point to every poll you see to Trump's numbers,'" Allen said.
That report is part of the gripping new book. It outlines how even before Clinton launched her 2016 campaign, she instructed her IT team to download top aides' emails from her 2008 run, trying to pinpoint which staffers leaked to media and track down infighting.
Then early on in 2016, while battling Senator Bernie Sanders in the primary, the authors claim Clinton admitted she couldn't get a handle on the new wave sweeping American politics.
"There's this rise in populism. She's on a plane with one of her close aides and she's basically questioning, 'What is happening in the country?' She doesn't quite understand it," Parnes said.
The book also details how Clinton herself created tension in her campaign by surrounding herself with rival aides inside and outside of the campaign. Some of those closest to her, like Huma Abedin, couldn't be honest with the Democratic nominee.
"She also had problems telling Hillary the truth, in that she was a gatekeeper for other people to get to Hillary Clinton," Allen said.
In their campaign autopsy, the writers found that unlike the Trump campaign, which ran primarily on gut instinct, the Clinton campaign relied heavily on voter data. In some key battleground states, that data hurt more than it helped, even causing a rift between Former President Bill Clinton and Campaign Manager Robby Mook.
"Her team decided that it was going to be more expensive and more difficult to persuade people who didn't agree with her, and spent more and more time focused on the people they thought they could turn out," Allen said.
But still, Clinton's message wasn't resonating with certain voters.
LLAMAS: "Do you think Donald Trump beat Hillary Clinton or do you think Hillary Clinton beat herself?"
ALLEN: "I think Hillary Clinton did so many things to damage her own campaign that she was not able to beat a flawed candidate in Donald Trump. A big part of that was not understanding what was going on in the electorate, the same thing that Donald Trump and in the primary, Bernie Sanders, were able to tap into."
In the final chapters is a play-by-play from election night, how Clinton apologized to president Obama for losing-and making that call to the future president.
"So she calls up Donald Trump and she says those words she never thought she was going to have to say, 'Congratulations, Donald,'" Allen said.
ABC News reached out to Mook for comment. As of late Wednesday morning, he had not yet responded. Some Clinton campaign aides who had not yet read the book said it may be overdramatized.
New book analyzes Hillary Clinton's doomed presidential campaign