Baltazar Enriquez starts most mornings with street patrols, leaving his home in Chicago’s Little Village on foot or by car to find immigration agents that have repeatedly targeted his largely Mexican neighborhood.

Wearing an orange whistle around his neck, the activist broadcasts his plans on Facebook.

“We don’t know if they’re going to come back. All we know is we’ve got to get ready,” he tells his thousands of followers. “Give us any tips if you see any suspicious cars.”

Moments later, his phone buzzes.

As an unprecedented immigration crackdown enters a third month, a growing number of Chicago residents are fighting back against what they deem a racist and aggressive overreach of the federal government. The Democratic stronghold’s response has tapped established activists and everyday residents from wealthy suburbs to working class neighborhoods.

They say their efforts _ community patrols, rapid responders, school escorts, vendor buyouts, honking horns and blowing whistles _ are a uniquely Chicago response that other cities President Donald Trump has targeted for federal intervention want to model.

“The strategy here is to make us afraid. The response from Chicago is a bunch of obscenities and ‘no,’” said Anna Zolkowski Sobor, who lives in a North Side neighborhood where federal agents threw tear gas and tackled an elderly man. “We are all Chicagoans who deserve to be here. Leave us alone.”

The sound of resistance

Perhaps the clearest indicator of Chicago’s growing resistance is the sound of whistles.

Enriquez is credited with being among the first to introduce the concept to the city. For months Little Village residents have used them to broadcast the persistent presence of immigration agents.

Short furious blasts both warn people and attract observers who record video or call out agents. Arrests, often referred to as kidnappings because many agents cover their faces, draw increasingly agitated crowds. Federal agents have responded with force.

Agents fatally shot one suburban man during an attempted traffic stop, while numerous others report tear gas, rubber bullets and physical force.

“We don’t have guns. All we have is a whistle,” Enriquez said. “That has become a method that has saved people from being kidnapped and unlawful arrest.”

By October, neighborhoods citywide were hosting so-called “Whistlemania” events to pack the brightly colored devices for distribution through restaurants and free book hutches.

“They want that orange whistle,” said Gabe Gonzalez, an organizer with Protect Rogers Park. “They want to nod to each other in the street and know they are part of this movement.”

Midwestern sensibilities and organizing roots

Even with its 2.7 million people, Chicago residents like to say the nation’s third-largest city operates more as a collection of small towns with Midwest sensibilities.

People generally know their neighbors and want to help. Word spreads quickly.

When immigration agents began targeting food vendors, Rick Rosales, got his bicycle advocacy group Cycling x Solidarity involved.

He hosted rides to visit street vendors, buying out their inventory to lower their risk while keeping them in business.

Irais Sosa, co-founder of the apparel store Sin Titulo, started a “neighbor-to-neighbor program,” with grocery runs and rideshare gift cards for families afraid of venturing out.

“That neighborhood feel and support is part of the core of Chicago,” she said.

Enriquez’s organization, Little Village Community Council, saw its walking group which escorts children whose family members are afraid to venture out, grow from 13 to 32 students in a matter of weeks.

Many also credit the grassroots nature of the efforts to the city’s long history of community and union organizing.

Trumps “border czar” Tom Homan said Chicago area residents were so familiar with their rights that making arrests during a different immigration operation in January was difficult.

So when hundreds of federal immigration agents arrived in September, activists poured their energy into an emergency hotline that dispatches response teams to gather intel, including names of those detained. Volunteers would also upload video of arrests to social media, warn of reoccurring license plates or follow their cars while honking horns.

Protests have also cropped up quickly. Recently, high school students have launched walkouts.

Delilah Hernandez, 16, was among dozens from Farragut Career Academy who protested on a school day. She knows many people who’ve had relatives detained. She held a sign with the Constitution’s preamble as she walked in Little Village.

“There is so much going on,” she said. “You feel it.”

A difficult environment

More than 3,200 people suspected of violating immigration laws have been arrested during the so-called “Operation Midway Blitz.” Dozens of U.S. citizens and protesters have also been arrested.

The Department of Homeland Security defends the operation, alleging federal officers face hostile crowds, as they root out violent criminals and immigration violators.

Gregory Bovino, the Border Patrol commander who’s brought aggressive and controversial tactics from a similar operation in Los Angeles, called Chicago a “very non permissive environment.” He blamed so-called sanctuary protections and outspoken elected leaders.

He defended agents’ tactics, which have been the subject of lawsuits.

“It’s definitely more violent here than it was in LA and it doesn’t show any signs of stopping,” he recently told the Associated Press.

Interest nationwide

Alonso Zaragoza, with a neighborhood organization in the heavily immigrant Belmont Cragin, has printed hundreds of “No ICE” posters for businesses. Organizers in Portland and St. Louis have asked for advice.

“It’s become a model for other cities,” Zaragoza said. “We’re building leaders in our community who are teaching others.”

The turnout for virtual know-your-rights trainings offered by the pro-democracy group, States at the Core, doubled from 500 to 1,000 over one recent month drawing participants from New York, New Jersey and Tennessee.

“We train and we let go, and the people of Chicago are the ones who run with it,” said organizer Jill Garvey.

Awaiting the aftermath

Enriquez completes up to three patrol shifts each day. Beyond the physical exertion, the work takes a toll.

Federal agents visited his home and questioned family members. A relative who is a U.S. citizen was handcuffed by immigration agents while out walking. His car horn no longer works, which he attributes to overuse.

“This has been very traumatizing,” he said. “It is very scary because you will remember this for the rest of your life.”