As part of President Donald Trump’s crackdown on immigration, the Federal Justice Department said in a memo on Tuesday it would investigate “sanctuary city policies”.
This refers to a decades long legal question of what role local government can take during immigration enforcement.

Following Trump’s November election win, the president-elect continued public planning of mass deportations. Several states and cities came forward and said they would not cooperate. Arguments that trace back to Trump’s first administration are resurfacing on the issue.

At odds with each other are two Constitutional principles; Amendment 10 in the Bill of Rights clashes with the Supremacy Clause of Article VI, Clause 2 of the Constitution. 

A 1997 Supreme Court case (Printz v United States) ruled that federal authorities cannot conscript— or “commandeer”— local personnel and resources to enact, enforce, or otherwise administer federal law.

“The federal government has to enforce its own policy. It can't require states to enforce policies,” Seth Kreimer said, a law professor at Penn Cary Law at University of Pennsylvania.

This precedent has been used a lot in immigration enforcement legal battles.

Cities will say citizenship is a federal law, and local law enforcement or courts do not have to use resources enforcing the law.

That said, the Supremacy Clause of the Constitution confirms that federal laws are enforceable in all of the United States.

“Local law enforcement can't prevent federal agents from taking action to enforce immigration law,” Kreimer said.

For example, local authorities do not have to give federal authorities full access to a police or court database. But, if ICE (Immigration & Customs Enforcement) came with a warrant for information on a specific individual, a city would have to comply with the court order.

“[Federal authorities] can’t call up a city and say ‘we’d like you to come along with us on our raids, we’d like you to arrest people on our behalf, we’d like you to house people in your jails,” Kreimer said.

There have been legal grey areas as to where a local government’s 10th amendment right ends and the federal government’s Supremacy Clause authority begins.

King County, Oregon tried to ban most ICE deportation flights from the local airport. The U.S. Court of Appeals for the 9th Circuit called the order discriminatory. In other cases though, states like California and Illinois have passed laws limiting if local authorities can inform ICE about undocumented immigrants or detain individuals for ICE.

One notable case was Galarza v Szalczyk, which was ruled on in 2014 by the U.S. Appeals Court of the Third Circuit.

In that case, an American citizen paid bail, but was held for an additional three days because Immigrations & Customs Enforcement (ICE) had put out a ‘detainer request’. The agency thought Galarza was an undocumented immigrant and asked the jail to detain him until they could send an agent out.

The local county said they were not at fault because they were following federal orders— but judges ruled that detention requests from ICE were just that; requests.

The case set precedent that not all communications from ICE had equal legal backing.

“They can ask you to do it. They can’t tell you to do it,” Kreimer said, who worked on the Galarza case. 

There are 10 counties and 3 cities in Pennsylvania right now that have some policy that clarifies how and if local law enforcement can interact with immigration enforcement.

Sanctuary

As the conversation around these legal technicalities continue, some immigration activists want to move aware from the term “sanctuary”, saying it can give an inaccurate impression. 

"People think that sanctuary cities are these places where undocumented immigrants can somehow hide from the authorities and be safe. That does not exist,” Cathryn Miller-Wilson said, executive director for the Hebrew Immigrant Aid Society in Philadelphia.

To sum, there is no city where immigrants who are illegally in the United States can avoid federal law enforcement.

Cities, counties, and states can say no to working with federal immigration officers.

But, they cannot ignore warrants and enforceable judicial orders.