By Scott Malone

BOSTON (Reuters) – The state of Massachusetts on Tuesday asked its top court to find that state authorities lack the authority to detain illegal immigrants who come in contact with the legal system to buy time for federal authorities to take them into custody.

The hearing amounted to a challenge to requests by the federal Immigration and Customs Enforcement (ICE) agency for courts and law enforcement agencies to keep illegal immigrants facing civil deportation orders in custody for up to 48 hours after their cases are resolved, a practice expected to step up under the administration of President Donald Trump.

The state argued that keeping someone in custody after his or her case is resolved amounted to a fresh arrest of the person without sufficient legal justification.

“Probable cause for civil removability is simply not a basis for arrest under Massachusetts law,” Jessica Barnett, an assistant state attorney general told the court. She noted that state law does not specifically give law enforcement agencies the power to arrest people facing civil deportation proceedings.

The U.S. Justice Department argued the detainer requests reflect basic practices of cooperation between various law enforcement agencies.

“From our perspective, all states have an inherent authority to police their sovereignty,” said Joshua Press, the lawyer representing the Justice Department.

The case was sparked by the arrest last year of Sreynuon Lunn, a man who Press said entered the United States as a refugee in 1985 and was ordered deported to Cambodia in 2008 after a series of criminal convictions.

Cambodia had declined to accept him and he was released. He was arrested in Boston on an unarmed robbery charge and ordered released in February after prosecutors failed to present a case. While he was waiting to be let out from his court holding cell, federal ICE officials took him into custody.

As a practical matter, his arrest by ICE makes the case moot but the Massachusetts Supreme Judicial Court agreed to take the case on premise that cooperation between law enforcement in the state and ICE would come up again.

Trump has made immigration enforcement a centerpiece of his presidency, vowing to wall off the Mexican border, deport an estimated 11 million undocumented people living in the country and cut off Justice Department grants to cities that fail to help U.S. immigration authorities.

Attorneys for Lunn and the state largely agreed on the matter, with both sides contending that state agencies lacked authority to comply with the ICE detainer requests. But Lunn’s attorneys went further, arguing that the detainer process violates the U.S. Constitution’s guarantees of due process because judges are not involved in issuing them.

“There is no fixing the constitutional problems here,” said Emma Winger, a public defense attorney representing Lunn.

Lunn’s attorneys have declined to answer questions about the status of the deportation case. The court did not immediately rule on the matter.

(Reporting by Scott Malone; Editing by Bernadette Baum and Marguerita Choy)