Joe Biden said the White House under President Barack Obama, when Biden was vice president, did not do enough to address the concerns of white working-class voters in the Rust Belt.

"A lot of people were left behind," the 2020 Democratic candidate told the New York Times when discussing the post-recession economic recovery. "In areas where people were hard hit, I don't think we paid enough attention to their plight."

Biden, 76, tried chalking up the disillusionment of white former Democratic voters to a messaging problem, saying Obama told him he didn't want to take "a victory lap [because] we have so much more to do," despite pleas the White House "explain to people how we got to where we were now and why it happened."

In August 2016, Biden told The Atlantic one of the chief appeals of Trump was his ability to speak with the average American and the economically disadvantaged .

"I was doing the interview on Morning Joe, and they asked the same question. And I said, 'Look, the truth is we just haven’t paid enough attention to these people. We haven’t spoken to them.” And everybody went nuts going, 'Aw Jesus! Hillary is going to think that’s an attack.'

"But I asked my team what did Hillary just say in her speech? She said we’re not paying enough attention — and the phrase I used that really upset them — I said, 'We’re not showing them enough respect.' And she also said we’re not showing enough respect.

"The truth is we are not showing enough respect. There is a new breed of Democrat that is represented by our administration, in my view, and the smart guys, the guys and gals who are Harvard, Yale, Penn graduates; the very, very well-informed, well-educated, elites of the party.

"They are the new version, if they don’t watch it, of the limousine liberals when I was coming up in the '60s. Because at its core there’s a disconnect with some really, really, really smart, good, decent people who are with us and part of the larger Democratic younger elite, the millennial elite who don’t understand the middle class anymore."

A month later, Clinton made remarks at a New York fundraiser that some came to see as a key factor in her defeat in November. “You know, to just be grossly generalistic, you could put half of Trump’s supporters into what I call the basket of deplorables. Right?” she said.

“The racist, sexist, homophobic, xenophobic, Islamophobic, you name it. And unfortunately there are people like that. And he has lifted them up.”

She added that the other half of Trump’s supporters “feel that the government has let them down” and were “desperate for change" in America. “Those are people we have to understand and empathize with as well."

[ Read more: Biden to critics who say he shouldn't have worked with segregationists: They 'don't know the history']