As President Donald Trump signals plans to order federal intervention in Chicago, experts say the likely escalation of immigration enforcement operations is setting the stage for a contentious dynamic between local police and federal authorities

Police watch during the 2025 Pilsen Mexican Independence Day parade Saturday, Sept. 6, 2025, in Chicago. (AP Photo/Carolyn Kaster)

CHICAGO (AP) — As President Donald Trump threatens to expand immigration raids and deploy the National Guard, Chicago has become the latest flashpoint in a broader national struggle over how far the federal government can push local authorities to cooperate with its immigration agenda.

For the Chicago Police Department, the challenge is acute. The force must preserve public safety in a city already under strain while avoiding the appearance of working hand-in-hand with federal immigration authorities, a stance that could erode community trust and ignite new protests.

The same balancing act has confronted other big-city departments in recent months. Local police in Los Angeles and Washington, D.C., were drawn into fraught arrangements with federal agencies that experts say left residents wary and, at times, undermined public confidence in their police.

Now, Chicago finds itself on the same path, with Illinois Gov. JB Pritzker objecting to any National Guard deployment and city officials bracing for how the added federal presence could reshape the dynamic on the ground. The outcome, policing experts warn, may determine whether Chicago police can maintain credibility in immigrant communities likely to be targeted by a president determined to show force.

“What the Trump administration is doing here is engaging in federal policing in a way that really rips at the seams of the relationships between state and local police and the federal government, between communities and law enforcement,” said Nayna Gupta, policy director at American Immigration Council. “Those kinds of standoffs and contentious practices is what erodes public safety.”

Sanctuary city conflicts

Over the course of the Trump administration’s immigration surges, Chicago officials repeatedly reaffirmed the city's so-called sanctuary policies that have been place for four decades. But as fear grew about looming U.S. Immigration and Customs Enforcement actions, the city's mayor has avoided detail about how local police will navigate tensions on the ground.

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Police walk along as people march during Illinois Coalition for Immigrant & Refugee Rights' "Chicago Says No Trump No Troops" protest Saturday, Sept. 6, 2025, in Chicago. (AP Photo/Carolyn Kaster)

Chicago’s policies bar local law enforcement from asking about or detaining someone for their immigration status or from supporting ICE, including by securing perimeters for raids, transporting detainees or sharing information about undocumented immigrants.

Mayor Brandon Johnson signed an executive order last week declaring city police would not collaborate with federal immigration agents. It also requires Chicago officers to wear uniforms and not wear masks to “clearly distinguish them from federal agents.”

“We will not have our police officers who are working hard every single day to drive down crime deputized to do traffic stops and checkpoints for the president,” Johnson said before signing the order.

Craig Futterman, a law professor at the University of Chicago, said any cooperation between ICE and local officers hurts public trust and blurs the lines between agencies.

“It can get really messy,” Futterman said. “There’s how sanctuary cities are supposed to work on paper vs. what happens in practice.”

Caught between protesters and ICE officials

Gupta said Chicago police will have to coordinate with federal agencies to some degree, even to respond to protests against immigration raids and detentions.

In the meantime, city officials say they're following a similar strategy to policing as the one in place around the 2024 Democratic National Convention, which cost the city about $27 million in officer overtime.

ICE detained at least 10 Chicagoans at an immigration office on June 4, drawing dozens of protesters and local elected officials to the street outside. Police didn't originally know it was an immigration action and left after realizing that, officials said.

Some protesters and local elected officials claimed they saw Chicago officers clearing the way for ICE agents and protecting their vehicles. Chicago City Council members demanded an internal probe into officers’ behavior.

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Chicago Mayor Brandon Johnson speaks during a news conference in front of Nash Elementary School, Friday, Sept. 5, 2025, in Chicago. (AP Photo/Carolyn Kaster)

Similar tensions played out in California, where hundreds of protesters clashed with federal immigration authorities in June, prompting Trump to deploy thousands of National Guard troops to Los Angeles, despite the objections of local authorities.

Los Angeles police made hundreds of arrests and dispersed demonstrations, including at locations where ICE agents were conducting raids.

Sanctuary city policies “don’t mean a local police officer will stand in between an ICE officer and a non-citizen,” which would be considered an obstruction of justice, said Rose Cuison-Villazor, a professor at Rutgers University Law School.

But whether local officers step in if they disagree with federal agents' interactions with protesters is also uncertain.

“Do they have the power to intervene?" Futterman asked. "These are really difficult legal questions. It’s a really fraught situation.”

Local police, National Guard interactions not clearly defined

Chuck Wexler, the executive director of the Washington D.C.-based think tank the Police Executive Research Forum, said local police leaders are used to working with federal authorities including joint task forces aimed at terrorism, drugs or organized crime. But if the National Guard is deployed in Chicago, its role in performing local policing hasn’t been clearly defined.

On Thursday, the District of Columbia sued to stop President Donald Trump’s deployment of National Guard during his law enforcement intervention there.

“As far as the National Guard as police, they have traditionally assisted in natural disasters, large scale disturbances and aiding law enforcement in support functions like traffic and crowd control," Wexler said. "I don’t recall the National Guard being deployed to deal directly with day-to-day crime issues.”

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Police walk the route during the 2025 Pilsen Mexican Independence Day parade Saturday, Sept. 6, 2025, in Chicago. (AP Photo/Carolyn Kaster)

Chicago Police Superintendent Larry Snelling has asked for more communication from federal authorities so “we don't have people running scared and it doesn’t create chaos on our streets.”

In Philadelphia, District Attorney Larry Krasner says the Trump administration's use of the National Guard is a threat to successful prosecutions of crime, risking witness statements being thrown out and evidence suppressed.

“None of these people are trained in evidence gathering procedures," Krasner said. "None of them are trained in Miranda warnings. None of them are trained in Fourth Amendment rights and procedures and illegal searches and seizures.”

Kenneth Corey, a former department chief with the New York City Police Department, warned that surging resources like the National Guard leads to an artificial and often temporary reduction in crime.

“Any time you surge resources like that you are going to see an immediate reduction in crime because it has a deterrent effect,” said Corey, who now works at the University of Chicago Crime Lab’s Policing Leadership Academy.

“But the problem is it’s short-lived. It can’t be sustained. When they leave, crime returns. You haven’t addressed the root causes of crime.”