Sen. Bernie Sanders (I-Vt.) said Tuesday that it would be “irresponsible” for his strongest supporters not to get behind former Vice President Joe Biden in the 2020 presidential race.

In an interview with The Associated Press, Sanders warned that progressives who “sit on their hands” in the months ahead of the November vote would just be enabling President Donald Trump’s reelection.

“Do we be as active as we can in electing Joe Biden and doing everything we can to move Joe and his campaign in a more progressive direction?” Sanders asked. “Or do we choose to sit it out and allow the most dangerous president in modern American history get reelected?”

Sanders formally endorsed Biden in a livestream on Monday, about a week after the Vermont senator dropped out of the presidential primary. Democrats hope the endorsement will help heal the party after the primary revealed vast ideological differences within it.

After Sanders suspended his campaign, many progressive individuals and groups announced they would not be endorsing Biden ― including Sanders’ own campaign press secretary, Briahna Joy Gray.

With the utmost respect for Bernie Sanders, who is an incredible human being & a genuine inspiration, I don't endorse Joe Biden.



I supported Bernie Sanders because he backed ideas like #MedicareForAll, cancelling ALL student debt, & a wealth tax. Biden supports none of those. — Briahna Joy Gray (@briebriejoy) April 13, 2020

“I supported Bernie Sanders because he backed ideas like #MedicareForAll, cancelling ALL student debt, & a wealth tax,” Gray tweeted on Monday. “Biden supports none of those.”

Sanders appeared to distance himself from Gray, saying she’s “not on the payroll” for the campaign, but the AP clarified with a Sanders spokesperson that all campaign staffers will still get a severance check next month despite no longer being on the campaign payroll.

The Vermont senator promised to support whoever is the Democratic nominee since he launched his campaign in early 2019 and has continued to stress the importance of getting Trump out of the White House above all else.

“I believe that it’s irresponsible for anybody to say, ’Well, I disagree with Joe Biden ― I disagree with Joe Biden! ― and therefore I’m not going to get involved,” Sanders told the AP.

With Sanders’ endorsement of Biden, the former vice president is now expected to make some concessions to appeal to progressive voters. The Vermont senator said the campaigns plan to create joint task forces to develop policy positions on key issues like the economy, criminal justice, climate change, immigration and education.

Biden has signaled that he’s open to shifting his campaign leftward, recently announcing his support for canceling student debt for many Americans who make less than $125,000 a year and adopting a proposal from Sen. Elizabeth Warren (D-Mass.) to repeal a bankruptcy law he once championed.

Still, Sanders and many progressives see ample room to push Biden further left. Eight progressive groups wrote a letter to Biden last week pushing him to adopt a list of left-wing policies while promising to spend $100 million to encourage young voters to vote.

Sanders also plans to stay on the ballot in states that haven’t yet held their primaries to gather as many delegates as he can before the Democratic National Convention this year. The hope is that gathering more delegates will help influence Biden’s platform and push him in a more progressive direction.

“I will do everything I can to help elect Joe,” he told the AP. “We had a contentious campaign. We disagree on issues. But my job now is to not only rally my supporters, but to do everything I can to bring the party together to see that [Trump] is not elected president.”