Story highlights Biden declined to run in the 2016 race

He also criticized President Donald Trump

(CNN) Former Vice President Joe Biden on Thursday indirectly knocked Hillary Clinton's failed 2016 campaign at a Thursday event, suggesting that the former secretary of state failed to talk to middle-class voters.

"What happened was that this was the first campaign that I can recall where my party did not talk about what it always stood for -- and that was how to maintain a burgeoning middle class," Biden said during an appearance at the University of Pennsylvania. "You didn't hear a single solitary sentence in the last campaign about that guy working on the assembly line making $60,000 bucks a year and a wife making $32,000 as a hostess in restaurant."

He added: "And they are making $90,000 and they have two kids and they can't make it and they are scared, they are frightened."

Clinton did attempt to speak to working class voters on the campaign trail, including through multiple bus trips through Pennsylvania, Ohio, Kentucky and West Virginia. But the overarching message of her campaign, especially at the end, was more often anti-Donald Trump than policy messaging toward these voters.

Trump ended up over-performing past Republican presidents with white, working class voters who were once reliable Democratic voters.

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