FLASHBACK: Bernie Sanders, Joe Biden’s Newest Endorser, Thrashed Him During Primary

Sen. Bernie Sanders (I., Vt.) officially endorsed Joe Biden for president on Monday, a dramatic step given Sanders's harsh criticism of Biden during the 2020 primary on health care, entitlements, trade, the Iraq War, and other issues.

"If we're going to beat Trump, we need turnout … and I just don't think that that kind of record is going to bring forth the energy that we need," Sanders told CNN in January.