“We spent months, some of us years, fighting for you because we believed you shared our dream for the world to be a place in which every human being can live in dignity. Your lack of moral clarity in the face of the genocide of Palestinians is a direct contradiction of the values your campaign stood for,” the former staffers wrote.

A spokesperson for Warren did not immediately respond to a request for comment.

The former staffers include field organizers, political directors and members of Warren’s data and analytics and social media teams. They worked at her national campaign headquarters and in 23 states, including Warren’s home state of Massachusetts and in the first two nominating states of Iowa and New Hampshire.

“We felt a responsibility as people who worked really hard on her campaign, and who really believe in her and trust her, to say something publicly, and to urge her to take a different approach,” Juliana Amin, Warren’s former Iowa organizing director, who helped draft the letter, said in an interview.

Notably absent from the letter are some of Warren’s top aides from her 2020 bid, including campaign manager Roger Lau and communications director Kristen Orthman, both of whom went on to work for the Democratic National Committee, as well as many of Warren’s early state directors.

Warren has drawn sustained criticism from the left for declining to follow other progressive lawmakers — including Massachusetts Reps. Jim McGovern and Ayanna Pressley — in calling for a ceasefire. Members of progressive Jewish groups including IfNotNow have demonstrated at Warren’s offices in Boston and Springfield in hopes of convincing her to call for a “ceasefire to prevent genocide in Gaza.” Progressive activists have also taken to social media to pressure Warren to call for deescalation and slammed her statement on the recent deadly explosion at a Gaza hospital.

“I appreciate the people who came to my office to share their perspectives and experiences — that’s what democracy is about,” Warren said in a statement to the Boston Globe about the demonstrations. “Israel has both a right to defend itself from terrorist attacks and an obligation to protect innocent civilians under the international laws of war. Palestinian civilians have a right to humanitarian aid including food, water, shelter, and medicine.”

Massachusetts’ senior senator now finds herself in the middle of an all-Democratic congressional delegation that’s increasingly divided over the situation in the Middle East, with McGovern and Pressley calling for a ceasefire on one side and Rep. Jake Auchincloss, a Jewish military veteran, saying Israel “can’t de-escalate” on the other.

And Warren’s attempts at striking a balance are only inflaming her base. The longer the Israel-Hamas conflict drags on, the more politically difficult the situation could become for her. Not because she’s on the ballot next year — she’s yet to draw a serious challenger from either major party — but because she is under a microscope as a major figure on the left.

Warren initially offered full-throated support for Israel in the days after Hamas’ Oct. 7 attack. In an emotional speech at the same pro-Israel rally where Sen. Ed Markey was booed for calling for deescalation, Warren said there is “no justification for terrorism ever” and pledged that America would be a “steadfast ally” to Israel.

As Israel moved to cut off all supplies of food, water and electricity to the Gaza Strip and urged the evacuation of 1 million people from the northern part of the enclave ahead of an expected military ground invasion, Warren’s language shifted. She called on Israel to “minimize civilian harm.” And she backed Biden’s move to send $100 million in humanitarian aid to Palestinians in Gaza and the West Bank.

For Amin, that’s not enough. “You can’t say we’re going to give $100 million of humanitarian aid … and also not disavow military support for the sophisticated army that has been bombarding what is essentially an open air prison,” she said.

“Elizabeth Warren is the kind of person who has historically always been willing to stand up and fight and do the right thing,” Amin added. “And I’m hopeful that she’ll do the same with this.”