Left-wing members of Congress are hardly afraid to break publicly with Joe Biden. They were the only Democrats to vote against the president’s bipartisan infrastructure bill in November 2021, insisting on a concurrent vote for a bigger social and climate policy bill. They have been outspoken in their demands for Biden to withhold additional aid to Israel until it ends its war in Gaza. And they were among the first voices blasting Biden for adopting a more centrist, enforcement-focused approach to the surge in migrants arriving at the U.S.-Mexico border.

But since Biden’s calamitous June 27 debate performance, Congress’ most prominent progressives have largely stayed in the background of the fight to get Biden, a mainstream Democrat, to withdraw from the 2024 presidential race. In fact, Congress’ two most influential progressive members, Sen. Bernie Sanders (I-Vt.) and Rep. Alexandria Ocasio-Cortez (D-N.Y.), have reiterated their support for Biden.

It’s a stance that has frustrated some ideological allies, while eliciting praise from others for the strategic discipline it reflects.

“I’m actually somewhat pleasantly surprised that progressives aren’t trying to score quick media victories” by crusading for Biden’s exit, said Bhaskar Sunkara, the president of The Nation, a progressive magazine.

These lawmakers’ support for, or neutrality toward, Biden staying in the race is especially notable because of how consistently the progressive left has pushed his administration in recent months to change how it is handling Israel’s invasion of Gaza. While lawmakers themselves have often been measured, a significant portion of their constituencies have been sharply critical of Biden on the issue, and it has been an albatross around his neck in making his case to certain Democratic blocs in 2024.

Multiple people familiar with the thinking of the most progressive members of Congress describe a host of tactical considerations influencing those lawmakers’ decisions — among them a lack of certainty on the best way to defeat former President Donald Trump at the polls, an acceptance of Biden’s defiance in the face of calls to withdraw, and a belief that progressive appeals for his exit would be ineffective.

“The moment [Vice President Kamala] Harris is the nominee and the media and right wing all turn their fire on her, are we actually in a better spot?” said a senior aide to a progressive House Democrat who, like others HuffPost spoke with for this story, requested anonymity for professional reasons. “It’s hard to know.”

There are also more self-interested concerns at play for these lawmakers: fears of the left taking the blame for a future Biden defeat — or that of a replacement nominee — should they speak up, and loyalty to a president who has largely been a good partner for progressives on domestic policy.

“From a progressive perspective, other than Gaza, the president has governed really well,” the senior aide said.

And then there’s sheer pragmatism.

Progressive lawmakers’ reticence to come out against Biden reflects an appreciation of the grave stakes of a Trump victory for “vulnerable communities, on working-class people, people of color and women,” according to a top staffer for a second progressive House member. Since Biden has made clear that he is not leaving, contributing to a conversation around his departure has become a “distraction” from the work needed to get him elected, the staffer said.

“These progressives are organizers, so they know how to organize under all conditions,” the top staff member said of stalwart left-wing lawmakers.

“This is not as if Ocasio-Cortez, [Washington Rep. Pramila] Jayapal, Sanders — whatever name you want to pick — gets to put forward their cherry-picked nominee. We all know that’s not the political reality that we are living in. However, they’re organizers, right? And so they’re going to be focused on harm reduction, they’re going to be focused on best possible outcomes, and they’re going to be focused on trying to build an administration that is responsive and that is accountable.”

The handful of progressive lawmakers who have spoken to the media about Biden in recent days range in their reactions to the turmoil around his campaign.

Some members of the Congressional Progressive Caucus have joined calls for Biden to withdraw from the presidential race. That list includes Rep. Raúl Grijalva (D-Ariz.) — a former CPC co-chair from an earlier generation of left-wing insurgents — and more mainstream progressives like Reps. Adam Smith (D-Wash.), Lloyd Doggett (D-Texas) and Mark Takano (D-Calif.), who are better known for their senior positions on various House committees than their ideological bona fides.

Other progressives have been somewhere in the middle, calling on Biden to improve while stopping short of demanding his withdrawal. Rep. Summer Lee (D-Pa.), a member of the left-wing “Squad,” said on a satellite radio broadcast last week that it was up to Biden to “show us” he has what it takes to win, and stated that she would support Harris as Democrats’ presidential nominee in the event that Biden drops out.

But what has understandably gotten much of the attention is the clutch of prominent left-wing lawmakers standing by his side and perhaps contributing to an environment where other House Democrats have gotten cold feet about coming out against him. Sanders has dismissed concerns about Biden’s age, arguing on Sunday against treating the presidential race like a “Grammy Award contest for best singer,” and instead emphasizing the policy differences between Biden and Trump. Ocasio-Cortez effectively treated Biden’s nomination as a fait accompli Monday, telling reporters: “The matter is closed. ... Joe Biden is our nominee. He is not leaving this race. He is in this race, and I support him.”

Also on Monday, Rep. Ayanna Pressley (D-Mass.), a fellow member of the Squad, described Biden as the nominee and warned people against “losing the plot.” Sen. Elizabeth Warren (D-Mass.) likewise described Biden as “our nominee” and an “excellent president.” And Sen. Jeff Merkley (D-Ore.), another leading progressive lawmaker, issued a joint statement of support for Biden with fellow Oregon Sen. Ron Wyden.

Rep. Ro Khanna (D-Calif.), who backed Sanders’ presidential bids and has ties to the influential Democratic donor network in Silicon Valley, joined “Pod Save America,” a liberal podcast co-hosted by alumni of the Barack Obama administration, to defend Biden as the best option to beat Trump.

“There is a deep authenticity. There’s a trust you have to establish with the American people. You have to convey why you’re doing it, what your vision is,” he told a skeptical co-host on Tuesday’s episode. “And it’s unclear to me that any of those [alternatives to Biden] ... untested, in four months would be able to do it.”

The top progressive staff member also echoed the Biden campaign’s suggestions that many of those taking the lead on pushing for his withdrawal are from the Democratic Party’s more upscale and white constituencies, rather than the Black, Latino or working-class parts of its base.

“Candidly, I think you see some young, white, moderate men doing this quick-to-raise-your-hand, ‘pick me instead, I’ll be your president, I’ll be your VP,’” the top staffer said, citing as examples Reps. Seth Moulton (D-Mass.) and Jared Golden (D-Maine). “But those are not the folks that are going to be putting their nose to the grindstone for the next four months, trying to bring together the diverse coalition of union workers, Black Americans, young folks, Gen Z student debtors that we need to win.”

While it is true that no Black member of Congress has yet called for Biden to withdraw and the Congressional Black Caucus has been leading the pushback against calls for Biden to drop out, not all of his detractors are white or male.

Nor does this account for the ripple effects: Lawmakers like Golden — one of five House Democrats running in a district Trump carried in 2020 — are critical to Democrats’ hopes for retaking the House, and have to consider Biden’s declining poll numbers in swing areas and the drag he could have on down-ballot candidates.

“I don’t think that those who are in safe, safe Democratic seats should be the ones closing this matter,” said the leader of a progressive organization active in electoral politics.

The progressive organization head expressed dismay with Ocasio-Cortez and other lawmakers treating Biden’s nomination as an immovable fact — and thus helping Biden intimidate front-line Democrats, who have the most skin in the game, out of calling for his withdrawal.

“I’m OK with silence. Progressives don’t need to lead on this, but they should do no harm,” the organization head said. “It’s really an open matter until the convention, and that’s the bottom line.”

Progressive lawmakers’ unexpectedly warm relationship with Biden looms over the conversation about what their role should be vis-à-vis the effort to drum him out.

Biden, a tough-on-crime rabble-rouser and faithful ally to the credit card industry during his long Senate tenure, was far from progressives’ first choice in the 2020 presidential primary. But his history of support for organized labor and openness to moving toward the center of the Democratic Party consensus at any given moment made him surprisingly willing to woo the left in the general election, including by inviting Sanders to serve on a policymaking panel to set priorities for his administration.

As president, Biden leveraged a 50-50 Senate to pass a raft of progressive-influenced bills, especially the $1.9 trillion economic relief package and the Inflation Reduction Act, the country’s first-ever climate bill. He won progressive praise for appointing anti-monopolists to key regulatory positions, presiding over the most pro-union Labor Department in decades, using executive authority to cancel student debt, following through on the withdrawal from Afghanistan and, most recently, protecting the undocumented immigrant spouses of U.S. citizens from deportation.

Throughout his presidency, Biden has kept lines of communication open to progressive lawmakers and activists, a key point of contrast with Obama. To wit, he celebrated Earth Day with Ocasio-Cortez and Sen. Ed Markey (D-Mass.), touting the creation of an American Climate Corps that had been a demand of climate activists and their allies in Congress.

Sunkara, who also founded Jacobin, a socialist magazine, has lost confidence in Biden’s ability to beat Trump and wants him to withdraw, but applauded progressive lawmakers for either saying nothing or standing by Biden.

“The alternative to Biden, the person they’re going to put in, if anything, might be worse for progressives in terms of their agenda than Biden himself,” Sunkara said. “The correct stance for progressives is, like usual, exactly what Bernie is doing, just saying we need to be talking about working-class issues and policies, what Trump is going to be for working-class people, and what a Democratic administration should be trying to do for working-class people, and just reducing it to bread-and-butter issues, no matter what the topic is.”