Vermont's Independent Sen. Bernie Sanders stopped short on Tuesday evening of endorsing Vice President Kamala Harris for president, claiming that she still had to work for his support. 

Harris became the presumptive Democratic nominee for president on Monday night, after delegates said they would support her at the Democratic convention now that President Joe Biden withdrew his bid for reelection. Biden endorsed Harris shortly after his departure.

Sanders said he will work hard to get Harris elected in November, and hopes she will defeat former President Donald Trump. But he said that he will not fully endorse her until she comes up with a plan to help working-class Americans.

"I look forward to strongly supporting her. But I think if she is going to win, she's going to have to focus a great deal of attention on the plight of the American working class, and come up with some very specific suggestions as to how she's going to address the reality that 60% of our people are living paycheck to paycheck," Sanders told reporters, NBC News reported. 

"[She has] to make it clear that she's on the side of the working class of this country. If she does that, she's going to win and I think she can win big," he added.

Sanders also noted that Harris' choice of a running mate will play into his decision on whether to formally endorse the vice president. 

The caveat to his endorsement is not the first time Sanders withheld his support. The senator made similar demands of Biden at the start of his campaign, but remained loyal to Biden throughout his reelection bid, even when others began to doubt his mental fitness.

Sanders recently claimed that Biden could still win if he expanded Medicare benefits, supported a bigger child tax credit, and increased taxes on the wealthy to preserve Social Security.

Other Democratic lawmakers have united around Harris as the party's new presumptive nominee, with 48 Democratic senators and 175 House members endorsing the vice president as of Tuesday night.

Misty Severi is an evening news reporter for Just The News. You can follow her on X for more coverage.