When WFP endorsed Warren in the fall, they held a ranked-choice vote of its national committee and online voters. Mitchell said it was clear from the beginning that there was strong support within the group for both Warren and Sanders. “Many strong Bernie supporters were also Elizabeth Warren supporters, and vice versa,” Mitchell said.

“Now that Elizabeth Warren has ended her campaign, we want to make the case to everybody — that’s all of the supporters of Elizabeth Warren’s change — that there’s a very clear contrast right now between Biden and Bernie. And Bernie’s clearly the person who believes in a Green New Deal, Medicare for All, has recently laid out a universal child care plan of his own,” he said.

On the question of whether the WFP endorsement might have any influence on Warren endorsing Sanders, Mitchell said they’d spoken to the Warren campaign. “Senator Warren knows our position,” he said. “She deserves the time and space to figure out what her next moves are. … And we’re sure that when she’s ready to make her next moves, she’ll make it known.”

WFP will be communicating to other Warren supporters to help ensure that Sanders is the nominee, Mitchell said.

The Progressive Change Campaign Committee, another progressive group that’s long been an ally of Warren and endorsed her in February 2019, sent an email over the weekend to members in Michigan urging them to “vote strategically” for Sanders. The group has not endorsed anyone since Warren ended her campaign.

“We are still heartbroken that Elizabeth Warren is no longer running for president,” it read, in part. “If your top priority is defeating Trump, and you want to ensure both remaining Democratic candidates are tested so we know the eventual nominee can go the distance, vote for Bernie Sanders on Tuesday to stop the premature ending of this primary election.”

Correction: March 9, 2020, 6:35 p.m.
A previous version of this article stated that PCCC endorsed Warren in February. It endorsed in February 2019.