The nation’s largest labor union, representing more than 3 million educators, is among several groups that filed a lawsuit against the Trump administration Monday to demand a federal court “immediately halt the government’s attempt to dismantle” the U.S. Department of Education—warning that the move by President Donald Trump is clearly illegal and “puts at risk the millions of vulnerable students.”

The National Education Association (NEA) said it is joining the National Association for the Advancement of Colored People (NAACP), AFSCME Maryland Council 3, and several public school parents in suing the administration days after Trump signed an executive order calling on Education Secretary Linda McMahon to take “all necessary steps to facilitate the closure of the Department of Education.”

That directive followed the slashing of roughly half of the workforce at the Department of Education and the termination of $1.5 billion in contracts and grants for educational programs that had already been approved by Congress, and came a day before the president announced that $1.8 trillion in student loan debt would be overseen by the Small Business Administration instead of the DOE, while the Health and Human Services Department will direct programs for students with disabilities.

The administration has insisted the DOE is rife with “bureaucratic bloat” and waste—the same accusations Trump and his billionaire ally, Elon Musk of the so-called Department of Government Efficiency, have lobbed at programs like Social Security, Medicaid, and other services for low-income and working Americans as they’ve sought to secure $4.5 trillion in permanent tax cuts for the richest Americans.

The steps the administration has taken against the DOE “constitute a de facto dismantling of the department by executive fiat,” reads the complaint filed Monday, noting that “the Constitution gives power over ‘the establishment of offices [and] the determination of their functions and jurisdiction’ to Congress—not to the president or any officer working under him.”

“America’s educators and parents won’t be silent as Donald Trump, Elon Musk, and Linda McMahon try to steal opportunities from our students, our families, and our communities to pay for tax cuts for billionaires.”

The attempted closure of the DOE is the latest of several actions taken by the Trump administration that violate the Constitution, said the NEA, because the department is a “congressionally created federal agency” and its dismantling “requires congressional approval.”

Federal courts have blocked Trump’s attempt to freeze federal grants and loans, noting that the president cannot halt funding that has been appropriated by Congress, and his deportation of Venezuelan immigrants to El Salvador under the Alien Enemies Act after opponents argued in court that Trump was “trying to write Congress’ limits out of the act.”

Aaron Ament, president of the Student Defense and Education Law Center, which is representing the plaintiffs in the lawsuit filed Monday, noted that McMahon “has acknowledged they can’t legally shut down the Department of Education without Congress.”

“Yet that is, for all intents and purposes, exactly what they are doing,” said Ament, “a brazen violation of the law that will upend the lives of countless students and families.”

Advocates have warned that while state and local governments oversee the vast majority of the U.S. public education system, shutting down the DOE jeopardizes funding an support for students who have disabilities, live in rural areas, and face discrimination.

It would also make it “impossible for the department to ensure that federal education funding actually is spent as Congress intended” and could “reduce access to Pell Grants, upend repayments for student loan borrowers, and invite fraudulent and predatory behavior from unscrupulous institutions of higher education,” said the NEA.

The union’s president, Becky Pringle, said Monday that “gutting the Department of Education will hurt all students by sending class sizes soaring, cutting job training programs, making higher education more out of reach, taking away special education services for students with disabilities, and gutting student civil rights protections.”

“America’s educators and parents won’t be silent as Donald Trump, Elon Musk, and Linda McMahon try to steal opportunities from our students, our families, and our communities to pay for tax cuts for billionaires,” said Pringle. “Parents, educators, and community leaders know this will widen the gaps in education, which is why we will do everything in our power to protect our students and their futures.”

Derrick Johnson, president and CEO of the NAACP, said Trump’s overarching goal in dismantling the DOE is “deliberately destroying the pathway many Americans have to a better life.”

“Education is power,” said Johnson. “The forceful elimination of thousands of essential workers will harm the most vulnerable in our communities. The NAACP and our partners are equipped with the necessary legal measures to prevent this unlawful attack on our children’s future.”