The U.S. Department of Justice has sued Colorado and the City and County of Denver, alleging their policies are interfering with the job of immigration officers in a case that could have ramifications for enforcement nationwide.

The lawsuit filed Friday in Colorado District Court claims both the state and Denver have enacted “sanctuary laws” in violation of the U.S. Constitution, the latest in a series of actions by the president cracking down on so-called “sanctuary” jurisdictions.

A “sanctuary city” generally refers to a jurisdiction that discourages local law enforcement from reporting an individual’s immigration status to federal authorities. This tension was on full display during a congressional hearing in March, when Denver Mayor Mike Johnston was called to testify about the city’s response to the influx of immigrants.

Along with Johnston, the lawsuit named Gov. Jared Polis, Attorney General Phil Weiser, the state legislature, the Denver City Council, the Denver Sheriff’s Department and Denver Sheriff Elias Diggins.

Similar lawsuits have been filed against Chicago and Rochester, New York.

Legal experts are closely watching the case, with some saying it is a critical test of the boundaries on the extent to which the federal government can compel the states to assist in detaining and deporting millions of people unlawfully staying in the U.S.

“The federal Department of Justice is arguing that various state and local laws violate the Supremacy Clause of the U.S. Constitution,” said University of Denver Constitutional Law Professor Ian Farrell. “This clause states that federal laws are the ‘supreme law of the land’ and therefore ‘preempt’ — make invalid — any state or local laws that conflict with federal laws.”

Three laws, broadly speaking, put Colorado under the category of “sanctuary” states: House Bill 19-1124, Senate Bill 21-131 and House Bill 23-1100. The three laws, respectively, prohibit Colorado law enforcement from complying with federal immigration detainers, prevent state agencies and law enforcement from sharing certain personal information with immigration authorities unless compelled by the courts, bar state or local entities from contracting or paying for immigration detention facilities, and prohibit local jails from holding inmates solely at the request of ICE.

The 2019 law also prohibits probation officers from providing “personal information about an individual to federal immigration authorities.”

Efforts by Republicans to repeal the laws have been unsuccessful. This year, Democrats are pushing legislation to limit federal immigration officers’ access into specific places, such as schools, and penalize, under specific situations, entities that provide the personal identifying information of immigrants.

The lawsuit blamed the local policies for the Venezuelan gang Tren de Aragua “seizing control of apartment complexes in Aurora.” It added: “The fact that a foreign terrorist organization could gain such a foothold in the United States of America is unacceptable. It is the direct byproduct of sanctuary policies pushed by the State of Colorado, and certain of its subdivisions.”

“Whether Colorado wins or loses this case will turn on a number of legal issues, including whether the Colorado laws really do conflict with the federal laws and whether the federal laws themselves are constitutionally permissible because, among other things, they force or ‘commandeer’ state officials to implement federal law and policy,” Farrell said.

Polis spokesperson Ally Sullivan told The Denver Gazette that Colorado is not a sanctuary state and that it regularly works with and values its partnerships with local, state and federal law enforcement agencies.

“If the courts say that any Colorado law is not valid, then we will follow the ruling,” Sullivan said. “We are not going to comment on the merits of the lawsuit.”

As of May, Colorado Attorney General Phil Weiser, a Democratic candidate for governor, has filed roughly a dozen lawsuits against the Trump administration’s orders.

“The Colorado Attorney General’s Office is committed to defending Colorado law and has done so successfully in the past in this area,” a spokesperson for Weiser’s office told The Denver Gazette. “We stand ready to do so again.”

It’s not the first time that Colorado or Denver had been on the radar of the Trump administration and its allies.

Congress summoned Johnston, along with mayors from Boston, Chicago and New York, to appear before the U.S. House Oversight and Government Reform Committee, which is tasked with investigating so-called “sanctuary” jurisdictions.

During that hearing, Republicans threatened Johnston with jail. A Republican from Ohio pressed Johnston about the release of an alleged Venezuelan gang member into “the streets” and how federal immigration agents scrambled to take him into custody. A video showed a man was released onto the streets outside the county jail. Upon seeing federal authorities, he ran, leaving ICE agents to chase after him.

The city earlier hired a law firm to represent the city in the upcoming congressional inquiry. Under the one-year contract with a maximum cap of $2 million, the city will pay lawyers a “discounted” rate of $1,000 per hour.

“Denver will not be bullied or blackmailed, least of all by an administration that has little regard for the law and even less for the truth,” Johnston said in a statement referring to the lawsuit. “Denver follows all laws — local, state and federal — and stands ready to defend its values.”

Then-Denver Mayor Michael Hancock had maintained that Denver is not a “sanctuary” city. In 2017, the Denver City Council passed an ordinance that prohibits “city employees from collecting information on immigration or citizenship status; prohibits the sharing of any other information about individuals for purposes of immigration enforcement; and, memorializes predominant practices by prohibiting use of city resources or city cooperation with civil immigration enforcement.”

A spokesperson for Johnston’s office told The Denver Gazette that the city is not considering any changes to its current policies regarding cooperation with federal immigration authorities, saying it is fully in compliance.

“We’re too early in the process to know the extent of what legal representation is necessary,” Jon Ewing, spokesperson for Johnston, said. “We’re hopeful that our city attorneys can handle this matter in house, while we stay focused on the issues Denverites care about, like public safety, downtown revitalization, affordable housing, and the Nuggets beating the Thunder in Round 2 of the NBA playoffs.”

Officials did not offer a statement regarding the naming of the Denver City Council as a defendant.

In an interview with Fox News, John Fabbricatore, a former ICE field office director, rejected the notion that the state has not been pushing back against federal immigration enforcement.

“They are obstructing federal law enforcement. They’ve done it since 2013,” he said. “The Trump administration is going to have a really good case on this because they’re going to be able to show actual cases.”

Meanwhile, Aurora Mayor Mike Coffman said he agrees with the DOJ on the lawsuit, adding his city should not be restricted from its ability to work with ICE.

Aurora has “never been a sanctuary city,” he said, and it has always cooperated with federal authorities.

“If somebody is in the country illegally, they are illegally here and we’re responsible for upholding the law,” Coffman said. “I do think the system is broken and it was way too easy to come into the country illegally. If people don’t want to enforce the laws or want to obstruct local authorities from enforcing the laws, they really need to advocate for change in the laws rather than not follow them.”

Aurora City Councilmember Danielle Jurinsky, who has spotlighted the tentacles of the Tren de Aragua in Aurora, said she, too, supports the DOJ lawsuit.

The Venezuelan gang’s activities in Aurora came to the attention of Trump, who, during a campaign in the visit last year, vowed to go after the international gang’s members.

Denver Gazette reporter Kyla Pearce and The Associated Press contributed to this story.