The three young idealists met before this all started, when the most pressing issues they faced were climate change, environmental justice and ensuring clean water for Detroit residents. They were all organizers of a sort: eager to do the unglamorous work of convincing people that they could dream bigger, and demand more from their government.

They came from very different parts of a segregated region. Justin Onwenu, 23, lives in Detroit, where 79 percent of the population is black. Bridget Quinn, 35, and Lauren Schandevel, 23, are from the overwhelmingly white suburbs of Macomb County, just north of the city.

But when the coronavirus shut everything down, they all noticed the same thing: All around them, people were overwhelmed and feeling helpless.

So they organized. And with nothing happening in person, they turned to Facebook, creating a public group called Metro Detroit Covid-19 Support. Within days it had grown to include thousands of people throughout the area. They pleaded for help with child care, offered suddenly scarce toilet paper and donated emergency cash funds with no strings attached. As the weeks wore on, many people requested or provided face masks, and increasingly, in desperation, asked for help with unemployment.

The pandemic has unmoored already fragile institutions across the country, forcing many Americans to turn to one another for help instead of to the government or nonprofit organizations. With the belief that the system is so broken that assistance will never come, hundreds of people have formed mutual aid societies, designed to allow people to find help themselves. Though the groups’ efforts vary widely, similar attempts to offer assistance have formed in dozens of states, including North Carolina, Texas and Arizona.

The groups are something of a throwback; such networks were popular in the heydays of communal activity, in the early 20th century and again in the 1960s and ’70s. The method is simple: Have something to give? Offer it up. Need something? Just ask for it.

There is nothing inherently political about mutual aid groups — their offerings are akin to bringing a casserole to a neighbor suffering a setback. But the newest crop has been formed largely by young progressives, and their proliferation points to a new kind of organizing that could reshape politics long after the pandemic. For young voters who saw their hope in Senator Bernie Sanders’s presidential campaign fizzle out just as the virus upended communities nationwide, the mutual aid societies are something of a balm — a kind of stake in the ground for their liberal ideals.

“For my age group, if we don’t walk away from this moment understanding there are things we really need to change, we will have failed,” Mr. Onwenu said from his apartment one recent afternoon. “It was just so clear early on: This is a generational moment and it’s going to be on us. You look at history and there are certain moments where the psyche of communities completely changes, and this will be one of them.”

In the Detroit area, one of the most segregated regions in the country, the organizers’ most radical idea was connecting people from the city with those in the mostly white suburbs, pushing the idea that they could help each other. From the beginning, the organizers saw the pandemic as magnifying a wide range of existing problems. They view the idea of rugged individualism with utter disdain.

After growing up in Warren, a working-class town in Macomb County, Ms. Schandevel enrolled in the University of Michigan as a kind of escape, not planning to return to a county long known as a stronghold for “Reagan Democrats.” But she became involved in organizing not far from her hometown and has worked for We the People-Michigan since graduating a year ago.

“It’s absolutely an extension of my politics, to try to build a community across race,” said Ms. Schandevel, who is white. “The whole construction of the suburbs emphasizes the nuclear family over all else. People lose a lot of empathy and trust with each other. That’s why our social safety nets are so eroded, we just don’t spend enough time with each other. I think trying to build up that trust is an inherently political thing.”

The way Ms. Schandevel sees it, the more empathy people have, the more likely they will be to vote for candidates who will enact the kinds of policies she supports.

Early on, the organizers created clear guidelines for the Facebook group: no live videos, nothing self-promotional. The idea was to create a replacement for a town bulletin board and to prove that pooling resources is better for everyone. They and a few other moderators would approve messages before they were posted, allowing them to filter out posts that did not request or offer help.

When people began dying from the coronavirus — more than 2,400 have died in Wayne County, which includes Detroit, and over 1,700 more have died in nearby Macomb and Oakland Counties — the organizers faced a difficult question: Should they allow obituaries in the Facebook group? They didn’t want to disrespect anyone. But they expected that the toll would be so high that death notices would overwhelm the board. So none appear. With information and questions about unemployment cropping up frequently, the moderators tried to streamline the message board by putting them all in one place — a “huge relief,” Ms. Schandevel said.

Still, the persistence of unemployment as the most pressing issue for so many members underscores a grim and practical reality: The virus’s impact will be felt for years, shaping public policy. And that public policy is what the organizers are setting their sights on.

“There is a renewed sense of urgency, because this has uncovered so many of the underlying problems we’ve had,” Ms. Quinn said. “Never has the need for universal health care and social safety nets been more clear.”

Slowly, the group has been tackling such issues head on, broadcasting speeches calling for universal health care. The organizers see the work as only beginning by explaining to those who lose their jobs and health care the benefits of a single-payer system.

What the moment has made clear, Mr. Onwenu said, is that a lot of things “we just didn’t think were urgent issues, that we thought people could wait for, that people weren’t feeling in their bones” are now rearing up. “All those systems need to be addressed,” he said. “I think communicating that very clearly to people is going to be our task.”

“Showing the need for health care that isn’t tied to employment status is one of the ways that we make the case for the thing that we already wanted,” he added.

More than anything, Ms. Quinn and her friends say they are pushing back against a sense of “rugged individualism,” the longstanding American ideal that each person is an island, responsible for and capable of pressing ahead in any circumstance.

They view such an ideal as a faulty narrative that has never been quite true, but is even less so today. It is in the suburbs, the women argued, that the idea that every family is an island has entrenched itself, overlooking those — single, gay or economically struggling — who fall outside the most narrow definition of family.

“Empathy can feel really rare and hard to come by because everyone is so isolated and atomized,” Ms. Quinn said.

So when armed protests at the State Capitol against stay-at-home orders made national news, Ms. Quinn felt, at least temporarily, infuriated. For one thing, the protests spoke to the kind of racial tensions she hoped to quell. But she saw how easy it was to fixate on the drama, on the attempts to incite fury among people desperate for work and a paycheck.

“I do feel like there’s this weird percolating energy that’s a little bit scary,” she said. “The race and class tension in southeastern Michigan feels extremely worrying — like it might, like, ignite at any moment.”

Ms. Schandevel chimed in. “On one hand, you have people who are out of work and cannot survive on the paltry stimulus check that the government is giving them, which is completely understandable,” she said. “But then you have a far-right contingency that is really exploiting that.”

The organizers were determined to provide an alternative for people who might be receptive to the protesters’ sentiments.

“The work we’re doing is very quiet, and that’s not something that people are going to pay attention to right now,” Ms. Schandevel said. “But it matters a lot — caring for each other will ultimately make a difference. It’s a long haul for changing people’s minds and changing the way that they view and treat their neighbors. But it’s definitely not insignificant and it’s not removed from political ideology at all.”