Colorado Republicans are once more seeking to repeal a set of laws that prohibits, in specific instances, cooperation with federal authorities in enforcing immigration laws.

The lawmakers, who are in the minority party in the Colorado legislature, have perennially tried but failed to convince the majority party to undo the laws.

They are seeking the repeal of the “sanctuary” laws as Colorado finds itself at the center of the national debate over illegal immigration. Since December 2022, roughly 43,000 immigrants — mainly from South and Central America who crossed the southern border illegally — have come to Denver, straining the city’s finances and putting the spotlight on Colorado.

No legal definition of a “sanctuary” city or state exists, but broadly speaking, it refers to a community that expressly refuses to cooperate with federal immigration authorities.

Colorado laws currently forbid a person from being arrested while at a courthouse or while going to, attending or coming from a court proceeding. They prohibit a law enforcement officer from arresting or detaining an individual based upon a “detainer request.” The laws additionally bar a probation officer from providing personal information about an individual to federal immigration authorities. Also, the laws say neither the state nor local governments may contract with a private entity for immigration detention services.

This year’s proposal from Republicans Sen. Mark Baisley of Woodland Park, Rep. Max Brooks of Castle Rock and Rep. Chris Richardson of Elizabeth would repeal these provisions.

In addition, the bill would reenact a 2006 law prohibiting local governments from adopting any policy that precludes officials or law enforcement officers from cooperating with the federal government on immigration matters. That law, repealed in 2013, required the police to report a person to immigration authorities if there was probable cause to believe the individual was not legally present in the U.S. Finally, the law carried a stick — local governments that violated its provisions could not get any grants administered by the state.

Whether the legislation advances this year — or how far — is unclear. Last year’s proposal never got out of committee.

The crisis over illegal immigration has been spilling into interior states, such as Colorado, Chicago and New York, over the last two years. It became a major issue in last year’s presidential race when President-elect Donald Trump identified Colorado as the launching pad for what he dubbed “Operation Aurora,” the start of what he promised to be the largest mass deportation in American history. 

Trump began mentioning Aurora on the campaign trail in September after a viral video surfaced showing heavily armed men suspected of being members of a transnational gang known as Tren de Aragua menacing residents of an apartment building in the city. Known as TdA, the gang originated from Venezuelan prisons.

More recently, Aurora Mayor Mike Coffman effectively blamed Denver Mayor Mike Johnston for the “national embarrassment” that his city suffered following reports of violence by the gang.

What “Operation Aurora” and mass deportations would look like remains to be seen. The Trump administration faces potential legal hurdles — the ACLU and other groups have been preparing for protracted court battles in anticipation of a second Trump presidency — and logistical ones, particularly since such a campaign would need the cooperation of local governments to be effective.

The latter is unlikely in Colorado. In 2019, Colorado adopted a law whose provisions fall within the broad outlines of what constitutes a “sanctuary” state. Several Colorado counties have sued the state over the law.

During his state of the state address last week, Gov. Jared Polis said he welcomes federal agents in Colorado to detain and deport “dangerous criminals.” Still, he insisted that the state would not support plans to send people who hadn’t broken any other laws back to their home countries.

In addition, Colorado’s most populous city — Denver — is also a “sanctuary” city.

A few weeks ago, Johnston, the Denver mayor, said he’s preparing the city for “all eventualities,” including losing federal funds, over his objections to Trump’s plans to conduct the largest-ever mass deportation in American history. 

Early in the city’s illegal immigration crisis, Denver officials decided taxpayers would assume the cost of temporary housing and feeding the immigrants. The city’s costs have so far exceeded $75 million. A new study by the Common Sense Institute, a research outfit in Greenwood Village, estimated that the nearly 43,000 immigrants who have come to Denver over the past two years have cost $356 million. That money includes hospital and education expenses.

Originally, local officials believed Denver’s draw was its proximity to Mexico and its status as a “sanctuary city.” But Texas officials in El Paso believe that the city’s offer of shelter and onward travel, while well intended, actually made Denver a magnet for immigrants.

Critics have argued that the mass deportation plan would be costly. At the same time, supporters maintained that it’s not only feasible but necessary, particularly because Trump vowed to fight illegal immigration, a top issue for American voters, during his campaign. Supporters also argued that illegal immigration enforcement in America’s interior cities, along with strict border controls, would serve as a deterrent, much as Denver’s offer of free housing and transportation drew tens of thousands of immigrants to the city over two years.

Reporters Nico Brambila, Ernest Luning and Deborah Grigsby Smith contributed to this article.