Two related but separate federal agencies are the primary enforcers of our immigration laws. One is the Customs and Border Protection Agency (CBP) whose diverse responsibilities include the collection of import duties and the regulation of international trade. It examines people and cargo at ports of entry for such concerns as smuggling and the curtailment of the spread of harmful pests. This agency also protects and patrols our Mexican and Canadian borders. It is part of the Department of Homeland Security (DHS). CBP does not have primary responsibility for the enforcement of immigration laws within the country.
That falls to the Immigration and Customs Enforcement Agency (ICE), which is also part of DHS. ICE is headed by Acting Director Todd Lyons. ICE has not had a Senate-confirmed director since 2017.
ICE has two primary components: the Homeland Security Investigations Division, which is concerned with transnational crimes, and the Enforcement and Removal Operations Division, which enforces immigration laws within the country. While ICE does not patrol the border, increasingly the border patrol (CBP) has been enforcing immigration laws away from the border, including in Minneapolis.
Under the One Big Beautiful Bill, ICE became the largest, most well-funded law enforcement agency in American history.
Although for a hundred years states tried to regulate immigration, the Supreme Court in the 1870s held that immigration and naturalization were solely under federal jurisdiction. Although immigration is a federal responsibility, ICE seeks the help of states and cities in immigration enforcement. Some jurisdictions, however, are reluctant to provide that help and claim status as a “sanctuary” city. While there is no legal definition of a sanctuary city, the term usually refers to a locality that refuses to cooperate or limits its cooperation with federal immigration authorities. Moreover, the use of the term “sanctuary” is misleading. An undocumented person does not get sanctuary from immigration laws by residing in a sanctuary city. The undocumented can be deported wherever they are in this country.
ICE officials have sought local assistance in several different ways. ICE might ask cities and counties to tell ICE when the localities have encountered an undocumented immigrant. Sanctuary cities usually do not honor these requests. They don’t share their databases with the federal officials. Some localities even forbid the collection of information about immigration status.
ICE often asks to interview people in local jails. Non-sanctuary places may freely allow that. Sanctuary localities, however, may not permit it at all or allow it only if the inmates voluntarily sign a consent form informing them that they don’t have to talk to ICE and are waiving that right.
ICE also lodges requests, called administrative detainers, asking to be informed when an inmate that ICE believes is deportable is to be released from a state or local lockup. Sanctuary cities differ in their responses. Many will tell ICE about the release of someone who has been convicted of a violent offense but not otherwise. Some sanctuaries will not tell ICE about the release of any inmate.
Trump officials suggest that this non-cooperation is illegal. That is not true. No law requires states and cities to cooperate with ICE, and no law probably can require that. That conclusion is based on the 1997 Supreme Court case, Printz v. United States.
At that time a federal law required “local chief law enforcement officers” to perform background checks on prospective handgun purchasers. The Supreme Court concluded that requirement was unconstitutional given the established constitutional principle that state legislatures are not subject to federal direction. The Supreme Court extended that maxim to local law enforcement, which the Court held is also not subject to federal direction. The Constitution does not empower the federal government to compel state law enforcement officers to fulfill the national government’s federal tasks. Assuming these principles still apply, the federal government cannot commandeer localities to enforce immigration laws.
The administration and other right wingers say, however, that sanctuary cities are making their communities unsafe by not helping deportations. Conservative media often scroll names of deportees along with the heinous crimes they supposedly committed. Trump’s press secretary has averred that the sanctuary jurisdictions are endangering their citizens by giving a safe haven to dangerous criminals. Trumpian attacks on the sanctuary states and cities are, therefore, “focused on protecting American communities from criminal aliens.”
Are the ICE actions focused on dangerous criminals? A fact-checking organization says that the administration has not provided enough information to substantiate that claim. The fact checkers say that the percentage of those detained without a criminal conviction or charges doubled in 2025 to 40%. However, most of the convictions are not for violent felony offenses. The Cato Institute has looked at the records of ICE detainees and concluded that a mere 5% of them had violent felony convictions. The New York Times also concluded from similar data that 7% had violent felony convictions.
Are sanctuary cities endangering their citizenry? Sanctuary jurisdictions maintain that their lack of cooperation is not only legal but is good policy. They point out that in sanctuary cities local resources are properly allocated to local priorities, not to enforcing laws that are the responsibility of the federal government. Sanctuary cities also maintain that they are safer because of their policies.
The jurisdictions highlight that deportation before a verdict or punishment, which often happens in non-sanctuary jurisdiction, deprives communities of the deterrence provided by the criminal justice system. Sending a person to his home country without serving a sentence here in the U.S. does not act as a deterrent to others.
The sanctuary jurisdictions also want undocumented people to feel comfortable cooperating with the local police. Without that cooperation crimes will not be reported and prosecuted. Undocumented immigrants won’t come forward to report crimes or become witnesses if, as a consequence, they will be deported. Criminals, whether citizens or not, will go free, and the community will be more crime-ridden.
Furthermore, a city may be healthier, safer, and more community-friendly if undocumented people are reasonably comfortable interacting with government authorities — not just police, but also schools, hospitals, clinics, employment agencies, and housing authorities.
Sanctuary cities point to study after study showing that sanctuary cities are safer than other cities and that sanctuary cities have, on average, more vibrant economies than non-sanctuary jurisdictions. The Trump administration, as it often does, avoids or denies the accuracy of such studies.
Finally, is there sanctuary for the undocumented in churches and elsewhere? President Obama issued orders that protected immigrants in hospitals, churches, courtrooms, funerals, weddings, and schools. Trump reversed that order. That there was an order and that it was reversed tells us something. We may have an image of Quasimodo swinging on a Notre Dame bell rope with Esmeralda under his arm and crying “Sanctuary,” but there is no accepted American legal principle that people are free from deportation (or prosecution for crimes) because they are sheltered in a house of worship.