On May 1, hundreds of thousands of immigrants and their allies are expected to take to the streets in a nationwide show of power. Immigrants have been marching on May Day for a decade now, first in 2006, when 1.5 million people took to the streets across the country to demand immigration reform. Until that year, May Day had been associated solely with International Workers’ Day; now immigrants have made it a day to demand their rights, too. That year marked a watershed moment; it was the first time immigrants and their loved ones took to the streets in such massive numbers. In the decade since, marching on May 1 has become an annual custom, and the day is a key national day of action for immigrant-rights activists and advocates.

This year is no ordinary year, though.

“As immigrants our livelihoods, our futures, our families—they’re all in danger,” says Jorge-Mario Cabrera, the director of communications at the Coalition for Humane Immigrant Rights of Los Angeles (CHIRLA). “May Day presents an opportunity for us to not silence ourselves and to remain vigilant.”

Hundreds of actions, including strikes, marches, vigils, and rallies, are planned for college campuses and in cities and towns across the country. It’s not just coastal cities either. In the lead-up to the May Day march in Phoenix, children of undocumented parents will gather at a church to share their stories before an all-night vigil, says Promise Arizona executive director Petra Falcon. In Milwaukee, where a major march is also being planned, the immigrant-rights organization Voces de la Frontera has been distributing letters in English and Spanish for workers to give to their bosses, asking employers to support workers who choose to participate in the day of action. Activists in Scranton, Pennsylvania; Raleigh, North Carolina; Newark, New Jersey; and dozens of other cities have been calling for a one-day strike.

“We believe that when the country recognizes it depends on immigrant labor to function we will win permanent protection from deportation for the 11 million undocumented immigrants; the right to travel freely to visit our loved ones abroad, and the right to be treated with dignity and respect,” said Movimiento Cosecha’s Maria Fernanda Cabello in a statement. According to the New Jersey–based group, hundreds of thousands of people around the country have pledged to participate in the strike.

Organizers and advocates say they expect high turnout this year.

“I definitely think this is going to be one of the biggest May Day marches,” says Kent Wong, executive director of the UCLA Labor Center, which is a member of the Los Angeles May Day Coalition. The turbulent Trump era and draconian attacks on immigrant communities all but guarantee a bigger and more passionate turnout than usual this year. As a candidate, Trump pursued a rhetorical stance that paints immigrants as dangerous criminals who threaten the very existence of the United States. As president, he’s translated that rhetoric into executive actions and initiatives that leave every one of the estimated 11 million undocumented immigrants vulnerable to deportation, regardless of their criminal background. With programs like VOICE—Victims of Immigration Crime Engagement—which the administration rolled out this week, the federal government has invited the general public to report crimes that suspected undocumented immigrants have committed.

Still, there’s no guarantee these May Day marches will be as large as the 2006 marches, says Artemio Arreola, the political director of the Illinois Coalition for Immigrant and Refugee Rights (ICIRR). Organizers of every march since 2006 have lived in the shadow of those marches, which were the largest May Day demonstrations in US history.

That year, immigrants had been in the streets for months fighting a bill that would have turned immigration violations from federal civil offenses into criminal ones. In addition to a host of other punitive policies, HR 4437, known as the Sensenbrenner Bill after its author, Wisconsin Representative James Sensenbrenner, also called for the expansion of the list of crimes that would allow the federal government to summarily deport noncitizens. With half a million people turning out in Los Angeles and a quarter-million in Chicago, the May Day marches got most of the media coverage, but mobilizations against HR 4437 had begun earlier than that. The bill passed the House in December 2005, and the marches to protest the bill began in March, Arreola remembers.

Almost a dozen years later, Arreola can still tick off the dates of those early mobilizations: March 10, March 25, April 10. At the April march, Arreola recalls, some 100 cities took part around the country. In May, marches against Sensenbrenner and against criminalization took place in more than 200 cities. That year, hundreds of thousands of immigrant families filled the streets wearing white T-shirts and waving Mexican and American flags alongside each other.

“All those previous marches helped on May 1,” Arreola says. And by then, recalls ICIRR senior policy counsel Fred Tsao, Senators John McCain and the late Ted Kennedy had begun working on an immigration-reform package. By May 1, Spanish-language radio hosts had been urging people into the streets, talking about HR 4437 and immigration reform daily over their airwaves. When immigrants took to the streets on May Day, they weren’t there just to fight back against the Sensenbrenner bill, but also to call for an overhaul of the nation’s immigration system.

“Los Angeles was phenomenal that day,” recalls Wong. “You had literally hundreds of thousands of people who did not go to work, so most of the city was shut down. It was as close as I’ve ever seen to a general strike.”

In the decade since, Congress has attempted, and failed, to pass immigration reform multiple times. As recently as 2013, the Senate passed a comprehensive immigration-reform package that would have included an opportunity for undocumented immigrants to obtain citizenship. The bill’s passage was historic—multiple attempts in the last half-decade prior had failed. But it stalled in the House. The federal DREAM Act, which would have extended a path to citizenship to some undocumented youth, known popularly as Dreamers, was passed in the House but narrowly fell in the Senate. And ultimately, the brightest national policy wins of the last decade were executive actions that President Obama took to grant those Dreamers short-term reprieves from immigration.

But, on immigration reform, “We didn’t deliver,” says Cabrera of CHIRLA. “We as the movement and also Democrats in Congress and Congress itself.” And amidst limited policy wins, President Obama deported a record 2.8 million people, far surpassing his predecessors, and further bolstered the deportation machinery that President Trump has been leaning on to aggressively pursue his own deportation agenda.

So what did those 2006 May Day marches give the immigrant-rights movement, if they didn’t pave the way for concrete policy wins? The dividends of those marches are hard to quantify, says Tsao. “The mobilizations were successful in building up the movements we know now.” In the decade while Congress wrestled over immigration reform, undocumented youth and their parents became a movement force, pushing a narrative strategy that countered right-wing depictions of immigrants. In the years prior to the 2006 march, immigrants and their advocates most often portrayed themselves as “workers” who contributed to the economy (as opposed to “job stealers”). But after 2006, many undocumented youth and their parents began to present themselves as members of families, as neighbors, students, and friends who were more than just economic actors. “May Day 2006 was the catalyst,” says Cabrera. “It was primarily immigrant families who came out and said, ‘We are really a force to be reckoned with.’”

That work, and the birth of a bolder, unapologetic undocumented-immigrant movement force happened in the intervening years—from 2006 to today. “Even when the marches started trailing off,” says Tsao, “we saw the emergence of youth leaders who took up the engagement in the political process.” They were, he says, “key factors in keeping this movement going.”

Today, no one, not even immigrant-rights advocates, is calling for immigration reform anymore. Immigrants and their allies are now defending civil rights such as due process and values such as democracy and inclusiveness. The policy agenda is no longer about winning citizenship or even legal status for the nation’s 11 million undocumented immigrants. It’s about defending families from separation. In those years while the immigrant-rights movement was becoming more robust, the right-wing forces which took over statehouses, Congress, and eventually the White House became more reactionary. Demographic change and the growing political power of people of color and Latinos inspired an anxiety and backlash that Donald Trump seized upon.

The new era has necessitated a new approach. Buoyed by the historic showing at the Women’s March and riled up by President Donald Trump’s anti-immigrant rhetoric and his administration’s immigration agenda, many groups have pledged to keep up the momentum of 2017’s string of mass demonstrations.

In Los Angeles, 100 organizations have signed on to join Los Angeles’ May Day Coalition, Cabrera states. “And that’s not usual,” he adds. A more typical figure is around 40 or 50. “This mobilization is not like every other Day.” Among the newcomers to this year’s May Day festivities are environmental groups, women’s and reproductive-rights organizations, teachers, and traditional African-American civil-rights groups.

Still, turnout remains a big unknown. Typically, the immediate success of mass protests is gauged by one indicator. “Obviously you measure the success by the number of participants,” says Cabrera. He, like many others involved in the planning of the upcoming May Day marches, cites the historic turnout at the international Women’s March in January as key to their lasting impact.

Turnout alone is too simplistic a measure to assess impact. A march is a one-time, if annual event, after all. In 2017, both Cabrera in Los Angeles and Arreola in Chicago speak with pride about the brand-new involvement of a broad range of organizations representing traditionally disparate interests. In both cities, the list of participating organizations is in the triple digits. It’s not just traditional immigrants’-rights allies like business, clergy, and labor who are turning out. New partnerships are forming. Jack Darin, director of the Illinois chapter of the Sierra Club, and Rose Joshua, the president of the Chicago Southside chapter of the NAACP, both confirmed that this year marks the first that their respective organizations will be participating in May Day actions. Immigrant-rights groups are stepping up their work to oppose the Trump administration’s attack on sanctuary cities, and increasingly partnering with black-led organizations that have been working on criminal-justice and police reform.

“One thing I’ve been struck by since the election is everyone is ready to see how these different movements intersect,” says Darin. “Our members see how our struggles and our goals intersect with these other constituencies. He, too, cites the power of the Women’s March for modeling this kind of intersectionality in movement strategy. “It showed a lot of people at a moment when we really needed to see it that we were all in this together, and combined, we really do represent the majority.”

Indeed, mass demonstrations serve multiple purposes. They can be as powerful for the participants as they are for the marchers’ intended targets. “Particularly if the demonstrations are peaceful and carried out in a spirit of protest, anger, but also in joy and camaraderie, those are some of the things that have made our marches so special,” Tsao says.

So regardless of turnout come May 1, Arreola already sees the immigrant-rights movement evolving. “I’m not sure if this May Day will be the same as in 2006,” he says. “But the good thing is a lot of people that never came before will do so today.”

“Believe me, we’re working on turnout too,” he adds. “But how many people make a difference?”

“One hundred? One hundred thousand? One million? How much is the key number? It’s not about that. More important,” Arreola says, “is how we’re going to keep working the next day.”