Colorado voters will weigh in on a constitutional amendment this fall that would require law enforcement to more closely cooperate with federal immigration authorities.

If passed, Amendment 81 would compel law enforcement to figure out if a person charged with a crime is “lawfully present” in the country, and tell the U.S. Department of Homeland Security within three days if someone in their custody lacks proper legal status or if they are unsure after attempting to find out. It would apply to people charged with violent crimes or if the person has a previous felony conviction.

As a constitutional amendment, it needs 55% of the vote to pass.

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The text of the amendment does not lay out how a police officer, sheriff’s deputy, correctional officer or district attorney should determine if someone is in the country legally. State and local authorities don’t track how many immigrants who lack permanent legal status are charged with violent crimes.

It is one of six measures backed this year by Advance Colorado, a conservative “dark money” group that does not disclose its donors. Last August and September, national dark money group A Common Sense America spent about $460,000 gathering signatures to get the amendment on this year’s ballot.

In an August 2025 post about so-called immigration “sanctuary policies,” the organization highlighted Colorado’s existing laws that limit cooperation between local law enforcement and federal immigration authorities.

Today, state and local law enforcement can truthfully tell victims and witnesses that we do not participate in federal, civil immigration enforcement ... If this passes, we would no longer be able to do that.

– John Walsh, Denver district attorney

Those laws “have stripped law enforcement of the ability to notify or assist federal immigration authorities—even when dealing with repeat felons,” the unattributed post says. “These policies shield offenders and deepen Colorado’s public safety crisis.”

Colorado law currently bars law enforcement officers from participating in civil immigration enforcement, and they cannot detain people based on a civil U.S Immigration and Customs Enforcement detainer request. State and local government agencies and employees are also prohibited in many cases from sharing certain personal information with federal immigration authorities.

Opponents launch campaign

A poll earlier this year from the Colorado Health Foundation found that 61% of Coloradans view the mistreatment of immigrants as a serious problem and 65% think misconduct from federal immigration officials is a serious issue.

Two issue committees are registered in favor of Amendment 81: the Eagle County Republican Women Club and A Brighter Colorado, which was registered in July to support all of Advance Colorado’s ballot measures. To date, A Brighter Colorado has received $250,000 from A Common Sense America and $20,000 from Advance Colorado, according to financial disclosures with the secretary of state’s office.

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There is virtually no public-facing campaign in support of the amendment. Advance Colorado did not respond to a request for an interview. Opponents launched their campaign, however, Thursday with a rally at the state Capitol.

“Unless a person charged with a crime happens to be carrying their passport, or unless local law enforcement can verify their immigration status within 72 hours, Amendment 81 would require us to report that person to ICE,” Denver District Attorney John Walsh said. “It inevitably means that law enforcement will be forced to report to ICE people who ultimately turn out to be American citizens and people who are lawful permanent residents of the United States. It is a recipe for abuse and racial and ethnic profiling.”

He said the amendment would erode trust in immigrant communities throughout the state and reduce their confidence to report crime.

“Today, state and local law enforcement can truthfully tell victims and witnesses that we do not participate in federal, civil immigration enforcement,” he said. “If this passes, we would no longer be able to do that.”

Three issue committees are registered in opposition to the amendment: Colorado Communities First, The People’s No, and Vote Common Sense. Those committees are financially supported by groups including ACLU Colorado, the Colorado Immigrant Rights Coalition and the Colorado Organization for Latina Opportunity and Reproductive Rights.

The Colorado Association of Chiefs of Police is neutral on the amendment and the County Sheriffs of Colorado has not taken a position on any ballot measures.