Sanders dropped out of the primary months earlier than he did in 2016, swiftly and wholeheartedly endorsed Biden, and set up policy task forces with him. Despite opposition from fellow progressives, senior Sanders aides have created super PACs to support Biden. And in an effort to avoid a repeat of the unruly Democratic National Convention during the last presidential election, Sanders’ team has told some of the delegates representing him there to sign a pledge swearing off attacks on Biden and other party leaders.

It has not gone unnoticed.

“Sen. Sanders has been a tremendous force in helping unify the party,” said Neera Tanden, president of the liberal think tank Center for American Progress and a longtime Hillary Clinton aide who has been a vocal critic of Sanders in the past. “I am grateful for his work to urge his supporters to support Biden and fight Trump. He knows the stakes of this election, has always said he will support the nominee, and has been a man of his word.”…

“Many of us who believed that Donald Trump could win in 2016 also believed that Hillary Clinton would win. And that has proven to not be the case,” said Jeff Weaver, Sanders’ longtime adviser and friend who created America’s Progressive Promise, a pro-Biden super PAC. “I feel a great responsibility having worked in this progressive space for 35 years — my entire adult life — at the side of Bernie Sanders to make sure that we stop what is happening in this country.”