What is a sanctuary city? A primer on the immigration showdown.

In the white-hot immigration debate, disagreement abounds around who it is that “sanctuary” cities, counties, and states actually protect. Are U.S. communities made safer by shielding immigrants unlawfully present there? Or does everyone face more safety threats as a result?

There is no legal definition of a sanctuary policy. But the term often implies limited cooperation with federal law enforcement concerning immigration. President-elect Donald Trump has blamed these policies for sheltering unauthorized immigrants, whom he wants to deport. Trump allies are warning there could be legal consequences for states and localities that stand in the way of federal immigration authorities. Immigrant advocates and liberal leaders have pushed back, as they did during the first Trump term. 

Amid the contention and distrust, though, there’s a sliver of common ground.

Both the incoming Republican administration and Democratic leaders agree that immigrants who commit serious crimes should be removed. Defining the scope of who else to include in Mr. Trump’s promised “mass deportations” – and the role sanctuary cities will play – is where consensus starts to fray. 

What does it mean to be a sanctuary jurisdiction?

There’s no one definition and the term is politically charged. It can mean policies that limit collaboration between local and federal law enforcement, as well as access to benefits like driver’s licenses and other IDs for unauthorized immigrants. 

The sanctuary movement began with faith groups in the 1980s. They sought to help Guatemalans and Salvadorans fleeing civil unrest, offering them food, shelter, and legal aid. Religious leaders mobilized as the Reagan administration limited access to asylum for these immigrants, whose countries’ military regimes the United States had backed.

Today, sanctuary jurisdictions are often led by Democratic politicians, including in California, Colorado, Illinois, and New York. Examples of sanctuary policies include: 

• Disregarding detainer requests from U.S. Immigration and Customs Enforcement (ICE). These requests ask agencies for notice before a deportable immigrant is released and for an additional hold of up to 48 hours so that ICE can take custody. 
• Banning new immigrant detention contracts set up to hold detained noncitizens.
• Prohibiting police or city workers from asking about immigration status.

Immigrant advocates claim that local cooperation with ICE has led to racial profiling by sheriffs and other civil rights violations. Proponents also say sanctuary policies support immigrants who might otherwise withhold reporting crimes, fearing deportation.

Critics push back against those concerns. They say ICE targets criminal immigrants and isn’t seeking to round up victims of crimes, who may be eligible for legal protection. Defenders of ICE also point to how sanctuary policies have let criminals return to the streets and harm U.S. citizens and immigrants alike. 

Some Democratic politicians are striking a nuanced tone on sanctuary policies, including the governor of Colorado. 

“We appreciate any federal assistance in apprehending and deporting people who have committed crimes and are a danger to Colorado,” Gov. Jared Polis told public radio. But removing otherwise law-abiding, longtime residents who work in construction, agriculture, or hospitality would “devastate our economy and our society,” he said.

Meanwhile, 26 Republican governors signed a statement last month supporting Mr. Trump’s commitment to deport “illegal immigrants who pose a threat to our communities and national security.” The GOP leaders added that they will do “everything in our power to assist in removing them from our communities.” In the U.S. House, among the immigration legislation reintroduced by Republicans this month, one bill seeks to make “sanctuary” jurisdictions ineligible for federal funds that would benefit unauthorized immigrants.

Some conservative-leaning cities and counties – within blue states – have passed measures declaring their opposition to sanctuary status. Yet those actions are symbolic, as local leaders can’t override state law, says Deep Gulasekaram, professor of immigration law at the University of Colorado Law School.

“Can a county or local official just decide to ignore state law because their personal feelings about immigration enforcement are not the same as state law?” he says. “The answer is no.”

Still, the legality of sanctuary policies under federal law is under debate. Mr. Trump tried to stop those policies last time. He says he will again.

What’s the Trump administration’s position?

During his first term, Mr. Trump sought to withhold certain federal funds from sanctuary jurisdictions. Legal fights ensued. Ultimately, most courts agreed that the federal government wasn’t authorized to condition law enforcement grants on immigration cooperation.

His allies appear to be gearing up again. America First Legal, led by Trump adviser Stephen Miller, says it has sent letters to over 250 officials “demanding their compliance with federal immigration law.” The group is warning jurisdictions that it’s a federal crime for anyone to “conceal, harbor, or shield from detection” unauthorized immigrants.

But other legal experts contend that it is unconstitutional for the government to compel state and local authorities to enforce federal law, and that the Supreme Court has ruled so. Meanwhile, the American Civil Liberties Union, in a memo published before the election, says it will urge state governments to “deny the federal government access to their law enforcement agencies and other state-held resources for purposes of immigrant detention and deportation.” 

Like his boss, incoming “border czar” Tom Homan is also opposed to sanctuary policies. 

Mr. Homan argues that without access to local jails, ICE pursues criminal immigrants in the communities where they work and live. That takes more time and resources, and can introduce ICE to other unauthorized immigrants previously not on the agency’s radar. And those people can turn into “collateral arrests.”

Most collateral arrests are made in sanctuary jurisdictions, wrote Mr. Homan in his 2020 book, “Defend the Border and Save Lives,” “because we are forced into the neighborhoods rather than operating within a jail.”

He calls for expanding cooperative agreements between local and state law enforcement agencies and ICE. That includes a program called 287(g). 

What’s the role of cooperative agreements, like in the 287(g) program?

The federal government creates and enforces immigration law. But the 287(g) program, created by Congress under the Clinton administration, lets ICE deputize state and local law enforcement for certain immigration actions. The partnership involves training and oversight; critics have questioned the program’s efficacy in terms of public safety goals. 

The 287(g) program includes agreements with 133 law enforcement agencies across 21 states, ICE reports as of December. Overall, participants make up a smidgen of the roughly 18,000 law enforcement agencies nationwide. 

The Biden administration placed the program under review in fiscal year 2021, which paused the onboarding of new partners. In contrast, the incoming Trump team may seek to expand the program, reports The Wall Street Journal. That includes the revival of a “task force model,” dormant since 2012, that allowed designated officers to question and arrest people they encountered on the job who they suspected had violated immigration laws.

Since the election, Jonathan Thompson, executive director of the National Sheriffs’ Association, says he’s become aware of several sheriffs who have “made themselves noticed” to the Department of Homeland Security about participating in 287(g). 

“Sheriffs are in the business of lowering risk of violence, criminal behavior, and incidents where people are harmed,” says Mr. Thompson. “Improved access to federal resources – that's what motivates them.”