Law360 (May 15, 2026, 9:11 PM EDT) -- The U.S. Department of Justice on Friday sued Connecticut in federal court over a recently enacted state law that subjects in-custody deaths to state oversight, requires federal agents to wear identifying badges, and bans law enforcement officers from wearing facemasks, calling the act "blatantly unconstitutional."

The complaint argues that the Supremacy Clause of the U.S. Constitution bans states from regulating federal law enforcement conduct. It seeks a judgment declaring four sections of the law, S.B. 397, "invalid as to federal agencies."

The lawsuit also seeks preliminary and permanent injunctions banning state officials from enforcing the bill. The federal government is also asking a judge to force the state to pay its costs and fees for bringing the lawsuit.

"For centuries, the Supreme Court has repeatedly recognized that states have no authority whatsoever to regulate the federal government's operations," the Justice Department argued. "A state law that directly regulates the federal government's operations is straightforwardly invalid."

Named as defendants are Gov. Ned Lamont and Attorney General William M. Tong. Also named are Chief State's Attorney Patrick J. Griffin and Connecticut Inspector General Eliot D. Prescott, a former state appellate judge. Under Connecticut law, the inspector general has the power to investigate law enforcement officers who use deadly force.

Though it targets four sections of S.B. 397, the lawsuit says other sections may be the subject of future lawsuits.

According to the government, Sections 3, 4 and 5 appear to "require federal agents to comply with Connecticut use-of-force policies" and "subject federal agents to state enforcement for noncompliance, including criminal penalties, even if federal agents fully complied with federal laws and policies on use of force."

Section 6 bans state and federal law enforcement officers from wearing "any facial covering or personal disguise while interacting with the public in the performance of such officer's duties," with exceptions for medical apparatuses, firefighting equipment, cold-weather gear and helmets for motorcycle officers. According to the DOJ, Section 6 further subjects federal officers to criminal penalties if they do not display badges and name tags when performing official duties.

Sections 3, 4 and 5 also violate the supremacy clause, while Section 6 violates the intergovernmental immunity doctrine, the DOJ argues.

The bill, which became Public Act 24-14 when signed, gives the Connecticut inspector general the power to investigate the death of any individual in law enforcement custody, including when they are in the hands of federal officers. If the inspector general's access to a scene is restricted, they can sue. They can also prosecute officers whose use of force is "not justifiable" under state law, according to the act.

Section 4 limits the use of deadly force to occasions where officers reasonably believe they must defend themselves or others "from the use or imminent use of deadly physical force." It also requires officers to reasonably determine that "there are no available reasonable alternatives to the use of deadly physical force," and it authorizes deadly force only when the officer "reasonably believes" there is "no unreasonable risk of injury to a third party."

Tong on Friday told Law360 "the state's actions are both fully lawful and necessary to protect public safety, and we will vigorously defend the law."

On May 1, the date the bill passed the Connecticut General Assembly, Tong said the "legislation reflects the unremarkable and uncontroversial proposition that no one is above the law."

"The sovereign state of Connecticut is prepared to use all legal tools available here to hold reckless federal actors accountable for violations of constitutional rights," he added.

Lamont's office on Friday referred Law360 to the attorney general's office for comment, but on May 4, the day he signed the bill, the governor said, "Connecticut will not stand by while federal agents violate the constitutional rights of our residents."

Commenting on social media site X, formerly known as Twitter, the governor also said on May 4 that the bill provides "protected areas, accountability measures, and the right to sue federal agents who break the law."

A spokesperson for the Connecticut Division of Criminal Justice, which houses the Office of Chief State's Attorney and the Office of the Connecticut Inspector General, did not respond to a request for comment Friday. The DOJ also did not respond to a request for comment.

In a separate April lawsuit, the federal government accused Connecticut and local officials of passing other laws limiting cooperation with federal immigration agents.

The federal government is represented by Stanley E. Woodward Jr., Brett A. Shumate, Yaakov M. Roth, Anna Edwards, Charles E.T. Roberts, Alessandra Faso and Alexandra McTague Schulte of the DOJ's Civil Division.

Counsel information for Connecticut was not immediately available.

The case is U.S. v. State of Connecticut et al., case number 3:26-cv-00758, in the U.S. District Court for the District of Connecticut.

--Editing by Adam LoBelia.

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