Former Vice President Joe Biden is going to have to make some “uncomfortable” concessions to win over the party’s left flank in 2020, Rep. Alexandria Ocasio-Cortez (D-NY) said in an interview published Monday.

Ocasio-Cortez, a key surrogate for Sen. Bernie Sanders’ (I-VT) erstwhile campaign and a prominent voice on the left, told The New York Times that although she’s committed to supporting the presumptive Democratic presidential nominee, whether or not he would receive her full-throated endorsement was a different matter.

“Beating Donald Trump is a matter of life or death for our communities,” the representative from New York told the Times. “I think it’s a difference between making an argument for harm reduction, and making the argument for, there’s actually going to be progress made for us.”

In the primary, Biden performed less well with Latino and young voters, Ocasio-Cortez pointed out, so concessions to these groups are a matter of winning in 2020, not simply “throwing the progressive wing of the party a couple of bones.”

“The whole process of coming together should be uncomfortable for everyone involved — that’s how you know it’s working,” she said. “And if Biden is only doing things he’s comfortable with, then it’s not enough.”

The congresswoman, who said she’d never spoken to the former vice president, singled out Biden’s recent announcement that he supported lowering the Medicare eligibility age to 60. Ocasio-Cortez called it an “almost insulting” attempt at outreach to the left, noting that in 2016 Hillary Clinton suggested a plan to let 50 or 55-year-olds purchase Medicare plans.

“So we’re talking about a ‘progressive concession’ that is 10 years worse than what the nominee had in 2016,” she said.

And while Biden supports a pathway to citizenship for “Dreamers,” that position is a decade old, Ocasio-Cortez said.

She pointed to Biden’s dismissive response to an activist at a November event, who criticized the millions of deportations during the Obama administration and asked whether the former vice president would commit to halting all deportations.

“You should vote for Trump,” Biden responded.

An argument for the pre-Trump status quo, the congresswoman said, would not suffice for many voters.

“I’m not trying to be divisive,” Ocasio-Cortez said. “But when you talk about lessons from 2016, one of the most divisive things that we can do is just smother and silence legitimate points of critique — especially from people whose lives are most at risk in this administration.”

“Because, for some people, this argument of returning to normalcy sounds like an argument of respectability politics and civility. And for other people, it sounds like, will my child be put in a cage?”