The administration of United States President Donald Trump has filed lawsuits against four Democrat-leaning states for refusing to issue confidential licence plates for vehicles carrying federal immigration agents.

On Thursday, the Department of Justice announced the complaint on its website, accusing Maine, Massachusetts, Oregon and Washington of defying the federal government’s demands.

Undercover licence plates, it argued, were necessary for the “operational effectiveness and safety” of agents “who have faced a wave of targeted harassment”.

But officials in the states have pushed back, arguing that agents for Immigration and Customs Enforcement (ICE) should not be allowed to carry out their activities in secret, without proper oversight.

The clash comes as Trump carries out a mass deportation campaign that critics have accused of human rights violations, including unwarranted violence, illegal arrests and denial of due process rights.

Obscuring agents’ identities

The Trump administration, however, has used concerns about ICE safety to crack down on efforts to identify agents.

Over the last year, for instance, the administration has pressured tech companies like Apple and Google to remove apps that tracked ICE agents, citing the risk of violence.

It has also dismissed a list of requested reforms from congressional Democrats, which called on ICE agents to be readily identifiable, stop racial profiling and abide by use-of-force standards.

The question of how to hold ICE accountable remains a politically divisive one. Trump officials have gone so far as to imply ICE could be immune from prosecution.

After an ICE agent shot and killed Minneapolis resident Renee Nicole Good, Vice President JD Vance initially told reporters, “That guy is protected by absolute immunity. He was doing his job,” though he later walked back that statement.

Confidential licence plates are one tactic the federal government uses to shield its agents from public identification.

Licence plate numbers are generally kept in databases accessible by state and federal officials. But a private licence plate obscures the owner of a given vehicle.

Several of the states the Trump administration sued on Thursday have argued that ICE agents are largely pursuing civil infractions, not criminal investigations, and are therefore not entitled to such protections.

Watchdog groups have also largely opposed such identity-masking, arguing that it allows ICE agents to commit violence without accountability.

States respond

On Thursday morning, in a news conference, Massachusetts Governor Maura Healey addressed the lawsuit by describing incidents where ICE has overstepped its authority, including by arresting US citizens and lawful residents.

“Last night, Donald Trump and the US Department of Justice filed a complaint suing our Registry of Motor Vehicles,” Healey said. “They want us to give ICE confidential licence plates so they can operate in secret in Massachusetts — in secret, even from our law enforcement.”

She then proceeded to draw a line between ICE’s actions and those of other federal law enforcement agencies.

“We support law enforcement doing legitimate law enforcement work. That’s not what we’re seeing from ICE,” Healey continued.

“So we’re not going to help them operate in secret as they take people off our streets without cause. We’re not going to allow them to make our streets and our communities and our neighbourhoods and our state less safe.”

Separately, in Oregon, officials have explained to the Trump administration that the state has temporarily paused all registration for federal vehicles, while a legal evaluation is under way.

“The DMV [Department of Motor Vehicles] pause is not intended to place federal law enforcement officers at risk or undermine ongoing criminal investigations,” Amy Joyce, an official with Oregon’s Department of Transportation, wrote in an open letter.

“The pause is necessary to ensure issuance of vehicle registrations and license plates to federal agencies fully complies with Oregon law.”

Oregon has so-called sanctuary laws that prohibit state agencies from collaborating on federal immigration enforcement, even if indirectly. A judicial warrant is needed for state participation.

In her letter, Joyce added that “the prospect of litigation in this area is real”, pointing to lawsuits the state has faced in the past.

She also underscored that giving federal vehicles undercover plates is discretionary, and that Oregon is not required to distribute them. Federal vehicles can still operate on Oregon roads without a state licence plate.

Federal vs state powers

But in issuing its lawsuits on Thursday, the Trump administration is likely to tee up a legal battle over the division of state and federal powers.

Officials with the Department of Justice have argued that not assigning ICE agents confidential licence plates is not only illegal, but violates the US Constitution’s Supremacy Clause.

That law gives federal law precedence over any state law that might conflict with its mandate.

But it is unclear whether such an argument will ultimately prevail in court. States are generally in charge of their own motor vehicle departments, while the federal government has the power to distribute its own plates for official use.

Acting Attorney General Todd Blanche, however, has argued that, by denying local licence plates, the states in question are illegally restricting the activities of the federal government.

“By denying undercover license plates to DHS [Department of Homeland Security] components, including ICE, while issuing them to their own state agencies, these governors are pursuing discriminatory and obstructionist policies against federal law enforcement,” Blanche said in a statement.

“These actions undermine federal immigration enforcement, allow dangerous criminals to escape justice, and terrorize American communities.”

The lawsuits themselves make the case that federal plates would compromise immigration agents during their undercover operations.

“Such law enforcement operations require federal law enforcement officers to blend into the environment to avoid premature detection that could undermine the mission and place them at risk,” the lawsuit against Massachusetts reads.

“If agents are forced to use a single traceable public plate, enforcement targets may be able to track and evade enforcement.”

But in response to that suit, Governor Healey said the issue ultimately comes down to whether federal agents will “respect the rule of law here in Massachusetts”.