The Maryland Attorney General’s Office has warned that banning federal immigration officers from wearing masks would be “difficult and likely unconstitutional,” undercutting efforts by Democratic lawmakers to constrain ICE enforcement in the state.

In a new letter to lawmakers, the attorney general’s office wrote that there is a “substantial risk” a mask ban would be found unenforceable in court.

Democrats in the General Assembly are fast-tracking two bills this session aimed at restricting Immigrations and Customs Enforcement, or ICE: The first would ban all law enforcement from wearing masks except in certain circumstances, like cold weather, and the other would prohibit local governments from entering into cooperative agreements with ICE.

But the attorney general’s letter highlights just how powerless state lawmakers are to curb federal immigration enforcement, even as a pair of deadly shootings in Minneapolis turned public opinion against ICE and its aggressive new tactics.

At a press conference Friday, Senate President Bill Ferguson said the attorney general’s advice letter does not pose a problem for the bill.

“Officers should be following Maryland law, full stop,” he said. “That is what the Constitution requires, and that is what this bill is about. It’s about setting the standard.”

Ferguson compared ICE agents’ actions to those of British soldiers in the colonies before the Revolutionary War, and said state lawmakers have an obligation to act now.

“This is why it matters so much if we do not stand up to a faceless, mask-wearing force that is exercising authority,” he said. “We are hitting times that are unprecedented, except from the founding of this country.”

The attorney general’s letter is not an official legal position, but offers advice to lawmakers as they try to craft legislation. The letter concludes that the mask ban “is not clearly unconstitutional” because regulating conduct to protect public safety is within the state’s authority, Assistant Attorney General Natalie R. Bilbrough wrote.

“However, it would be difficult and likely unconstitutional for the State to enforce a masking prohibition against federal agents like Immigration and Customs Enforcement agents, or to require them to adopt certain anti-masking policies,” she continued.

Federal law overrides conflicting state laws under the Supremacy Clause of the U.S. Constitution, Bilbrough wrote, and “intergovernmental immunity” prevents states from regulating the operations of federal agencies.

The fact that the bill bans masking by all law enforcement officers, and not just federal cops, makes it more defensible, but courts generally defer to the federal government on immigration issues, she wrote.

California passed a law banning law enforcement officers from covering their faces last year, but the Trump administration has already sued to block it. State lawmakers in Maryland have said they expect similar litigation if they pass a mask ban here.

Maryland’s attorney general would be responsible for defending the law if it were challenged in court.

Senate Judicial Proceedings Committee Chair Will Smith said he is confident the attorney general’s office will vigorously defend the masking ban in the event of a lawsuit. He acknowledged that it is not clear how the legal issues will shake out.

“This is a very uncharted path that we’re going down, so the courts will figure this out,” he said. “It’s incumbent upon us to protect the rights and values of Marylanders.”

The Senate bill originally included a criminal penalty for law enforcement officers who violate the law by wearing masks, but a committee amended the proposal to make it a civil offense with a $1,500 fine.

Republicans oppose the bill and have questioned how enforcement of a mask ban would play out. Sen. William Folden, a Republican who represents Frederick County, said the bill would create an impossible situation for local police officers tasked with issuing civil citations against federal agents.

If an ICE agent refused to identify himself to receive a citation, and a local cop hindered a federal operation in an effort to enforce the ban, the officers could end up trying to arrest each other, Folden said.

“We could literally have a scrum in the streets over their authority,” he told fellow senators during floor debate this week.

The Senate could pass its mask ban as soon as next week. The House is also moving on its own version, which still includes a criminal penalty.