BOSTON—Massachusetts will become the second state to sue the federal government over President Trump’s executive order barring immigration from seven predominantly Muslim countries. In a press conference on Boston’s Beacon Hill, Massachusetts Attorney General Maura Healey declared the order “harmful, discriminatory, and unconstitutional” and announced that her office will join a suit filed Saturday night by the Massachusetts ACLU and immigration lawyers seeking to have the order overturned.

“No one is above the law,” Healey said, when asked what message she would send the president. “We must be prepared to take action at all times when and if someone acts in ways that are unlawful or unconstitutional.”

On Monday, Washington became the first state to file against the order. Hours later, Trump was forced to fire Acting U.S. Attorney General Sally Yates when she refused to defend the order in court. The immigration ban created chaos at airports around the nation this weekend as travelers—including green card holders who call the U.S. home, visiting family members of American citizens, and refugees who had gone through years of vetting to obtain visas—landed only to be told that their papers had become void while they were in the air. On Saturday night, judges in New York, Virginia, Seattle, and Boston moved swiftly to stay parts of the order and halt deportations. The restraining order imposed by Boston judges gave immigrants approved before the ban at least a week to enter the country. Healey’s office will seek to extend that window while arguing that Trump’s order must ultimately be overturned in its entirety.

Healey, a Democrat who addressed protesters at Boston’s Logan Airport on Saturday, said her office would join a suit originally filed on behalf of two Iranian engineering professors at the University of Massachusetts–Dartmouth. Mazdak Pourabdollah Tootkaboni and Arghavan Louhghalam were detained on their way home from a conference in Marseilles, France, on Saturday despite their status as lawful permanent residents.

In a state perhaps best known for its universities and hospitals, the order’s impact constitutes “a serious interference with our economic lifeblood,” Healey said. “But at bottom, what this is about is a violation of the Constitution, discriminating against people based on their religion or because of their country of origin.” Even Republican Gov. Charlie Baker made a tepid statement of support for the legal action on Monday, telling local radio station WGBH that the suit “in my opinion is the best and most significant way we can support the rule of law.”

Massachusetts will likely not be the last state to sue the federal government over Trump’s immigration order. And the order may be only the first of many actions that induce liberal attorneys general to take Trump to court.

This is a developing story. Information will be added once Massachusetts’ complaint has been filed.