Vermont Attorney General T.J. Donovan joined 15 other attorneys general on Monday in supporting two states challenging President Donald Trump’s controversial executive order on immigration and refugee resettlement.

Washington and Minnesota successfully sued on Friday to temporarily lift Trump’s travel ban, which had halted all refugee arrivals and immigration from seven Muslim-majority countries.

Trump’s team appealed the order to the U.S. Court of Appeals for the Ninth Circuit. Arguments in the matter have been scheduled for 6 p.m. Tuesday.

“I am proud to support Washington and Minnesota in their legal action against this unconstitutional order,” said Donovan in a written statement. He could not immediately be reached for further comment.

The 16 attorneys general who signed the amicus curiae — “friend of the court” — brief argue that the ban is unconstitutional and that reinstating it would harm state colleges, universities and medical institutions, and lower state tax revenues from students, tourists and business visitors.

“If this court were to grant a stay, it would resurrect the chaos experienced in our airports beginning on the weekend of January 28 and 29, and cause harm to the states — including to state institutions such as public universities, to the businesses that sustain our economies, and to our residents,” the filing reads.

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

The case could ultimately end up before the U.S. Supreme Court.