Des Moines—“These are the people who are tired of not getting their phone calls returned,” said Jean O’Donnell, a racial justice activist in Des Moines, as she watched thousands of activists fill a sprawling convention-center ballroom for an appropriately titled “People’s Presidential Forum.”

The crowd was multiracial, multiethnic, urban and rural, all ages, mostly from Iowa but also from other states where People’s Action is working with its growing network of progressive organizations on a 2020 agenda that the group’s national director, George Goehl, sums up as “defeating white nationalism and advancing a big, bold agenda.” They had all come to Des Moines for what would turn out to be the most grassroots-focused, poignant, and revealing forum so far in the campaign season. As activists who have “committed to organize 47,310 volunteers to move 2,829,105 voters to vote for candidates who will enact the People’s Platform” in 2020, they arrived with a shared purpose: to determine whether any of the Democratic presidential candidates are prepared to serve as “a movement president.”

But how do the people who are tired of not getting their phone calls returned achieve the “radical, total liberation” proposed by Bryce Fields, an organizer with Illinois’s One People’s Campaign as they roused an overwhelmingly working-class crowd? The answer was in the room, where so many of the people were associated with Iowa Citizens for Community Improvement (CCI) Action and Iowa Student Action. Because the vast majority of the 2,500 people who attended Saturday’s forum will participate in next February’s Iowa caucuses, Iowa CCI Action President Barb Kalbach was right when she told the crowd, “We are a mighty force.”

That explains why four Democratic presidential contenders, Vermont Senator Bernie Sanders, Massachusetts Senator Elizabeth Warren, former housing secretary Julián Castro, and South Bend, Indiana, Mayor Pete Buttigieg, showed up Saturday to face tougher inquiries, more pointed follow-up questions, and deeper scrutiny than any had experienced in this year’s vapid televised debates. The format—the most impressive I have seen at a forum so far this year—had the candidates listen to testimony from immigrants, refugees, fast-food workers, daughters caring for ailing parents, moms struggling to find adequate housing, and people who have been racially profiled. Farmers who were well into their eighties and LGBTQ+ students who were just into their 20s asked precise questions about issues raised by the testimony. There were no moderators, no panels of cable news show hosts, no “gotcha” questions.

The candidates who took the time to participate in this forum responded ably and said important things. But the most important news from Iowa over the weekend was not a pronouncement from a candidate to replace Donald Trump, nor even the new Des Moines Register poll that put Warren narrowly ahead of Biden in Iowa—22-20—with Sanders in third place.

The big news had to do with a technical twist in the caucus process that illustrated why the People’s Presidential Forum was such a big deal. With approval from the Democratic National Committee, next year’s caucuses will be a good deal more democratic and more inclusive than in the past. Under the plan announced Friday, traditional precinct caucuses will still be held, but there will be an option for grassroots groups to petition for “satellite caucuses” at nursing homes, work sites, and community college campuses where people who cannot get to caucuses can participate. That also means organized people in Iowa will have an opportunity to make real the call and response led by Cherie Mortice of Iowa CCI: “Who’s got the power?” “We’ve got the power.” And because Iowa CCI Action (along with People’s Action and its other partners) is expected to make a critical endorsement in early November, the candidates who “get it” showed up.

So how did they do?

Julián Castro

The former HUD secretary got high marks when he answered “yes” to tough questioning about making sure that a clean-energy economy will be democratically controlled—especially when he mentioned the role of municipally owned power plants. And he earned a spontaneous standing ovation when he responded to the poignant testimony of Jackie Torres Toro—who fled gang violence in Honduras, which threatened her entire family—with a detail-oriented promise to “lay down a vision [for immigration reform] that represents something completely different from this president.” The response was far more tepid, however, when Castro answered questions about “Medicare for All” health-care reform. Talk of keeping private insurers drew no applause and a few moans from the crowd.

Pete Buttigieg

The South Bend mayor faced the toughest questioning of the day. He got a good response when he spoke on the “moral urgency” of addressing environmental racism. And there was plenty of applause for his proposal to “expand who can unionize” with new models for collective bargaining that benefit gig workers. But it did not go so well when he was grilled on policing in South Bend, his caution about supporting a universal plan for free college education, and his willingness to keep private insurance companies. When Buttigieg described his “public option” approach to health care reform, there were shouts of “It isn’t enough!” Then the crowd erupted with chants of “Medicare for All.”

Elizabeth Warren

The Massachusetts senator delighted in the questions she took from the grassroots activists about racial justice, long-term care, worker rights, and saving family farms. Again and again, she lit up and replied, “I have a plan for that.” Warren’s plans were often more modest than those proposed by People’s Action, however. On the issue of housing policy, Tara Raghuveer, the director of KC Tenants, listened intently as Warren was asked if she would back a sweeping “Homes Guarantee” proposal to build social housing units, invest in public housing, and establish a system for universal rent control. “Warren did not commit,” noted Raghuveer. However, the Massachusetts senator proved adept in responding to questions about farm policy, especially when she spoke of using existing antitrust laws to address consolidations of ownership and influence by corporate agribusiness. “Right now, we have the laws to break up Big Ag, and I have the courage to enforce those laws,” declared Warren, to some of the loudest applause of the day.

Bernie Sanders

The Vermont senator took the forum stage to an extended standing ovation and robust chants of “Bernie!” He faced detailed questioning, and the famously impatient senator also had to listen more than talk. But he gave himself to the moment and delivered answers that echoed the “People Before Profits” message of People’s Action and its state partners such as CCI Action, especially when he declared, in answer to a question about taking on fossil fuel companies, “Their short-term profits are not more important than the future of the planet.” And the room shook with cheers after he declared, “Our job now is to stand up to the greed and corruption of insurance companies and the pharmaceutical companies and to tell them that we’re coming after them because health care is a human right.”

People’s Action and its allies will hold more presidential forums (including a pair next month in New Hampshire and Nevada) before delegates head to a November gathering where the group will determine whom to endorse. All the candidates had pockets of support in the Des Moines crowd. But it’s fair to say that Sanders connected with a lot of folks Saturday. When the five-hour forum was done, I asked Tiana Caldwell, a 41-year-old tenant rights activist from Kansas City who had been on stage to ask questions about the “Homes Guarantee” proposal, which candidate impressed her the most. “Bernie,” she replied. “He’s for a Homes Guarantee. He talks about it. He’s got a real commitment. It’s hard not to love that.”