The same argument was made by the state of Washington, which won a federal court order last week temporarily halting Trump’s executive order. Trump has appealed to the regional federal appeals court, the US Court of Appeals for the Ninth Circuit, which is based in San Francisco. The state of Minnesota later joined Washington’s lawsuit. Oral arguments in the appeal are slated to be made in a hearing Tuesday afternoon.

In the filing, the 16 attorneys general argue that Trump’s Jan. 27 executive order temporarily prohibiting refugees and immigrants from seven nations from entering the country would have an adverse affect on the states’ interests, as well as the interests of each state’s residents and institutions, such as universities and businesses whose students and employees would be affected.

The filing of an amicus curiae brief, or a “friend of the court” brief by the 16 attorneys general allows them to make arguments as interested parties, even if they are not plaintiffs in the case.


“Although the amici states’ residents, institutions, industries, and economies differ in various ways, we now all stand together in facing concrete, immediate and irreparable harms from the executive order,” the states argued in the 29-page court filing. The state of Hawaii, which initially sought to join the case as a plaintiff, was later allowed to file its own amicus brief.

Healey said in a statement Monday that, “no president or administration is more powerful than our laws and our Constitution. As state [attorneys general], it is our job to hold this administration accountable and stand for the interests of our states and our residents. We are united in this effort.”


Besides Massachusetts, the other states are New York; Pennsylvania; California; Connecticut; Delaware; Illinois; Iowa; Maryland; Maine; New Mexico; Oregon; Rhode Island; Vermont; Virginia, and the District of Columbia.

Healey joined a lawsuit filed by the American Civil Liberties Union of Massachusetts in federal court in Boston filed last week on behalf of immigrants affected by the ban and an international aid organization, Oxfam, which said the ban would affect its employees and associates.

US District Judge Nathaniel M. Gorton refused to extend a restraining order that was filed in that case, saying Trump was likely to prevail in court. Almost simultaneously, however, US District Judge James Robart in Seattle agreed to issue a nationwide restraining order halting Trump’s order, siding with the state of Washington’s separate claim that the state would be adversely affected.

Milton J. Valencia can be reached at milton.valencia@globe.com. Follow him on Twitter @miltonvalencia.