The Trump administration filed a brief Thursday with the Supreme Court in support of a coalition of 20 states that has sued the federal government arguing that Obamacare is unconstitutional.

The brief supports the coalition of states, led by Texas Attorney General Ken Paxton in February 2018, in its claim that the Affordable Care Act (ACA), also known as Obamacare, is in violation of the Constitution since the Republican tax overhaul in 2017 repealed the individual mandate, the cornerstone of the law.

In 2012, Chief Justice John Roberts provided the decisive fifth vote in the Supreme Court’s stunning ruling that Obamacare’s individual mandate requiring the purchase of health insurance is constitutional as a “tax,” rather than a “penalty.”

Paxton filed another brief Thursday, asking the Court to declare Obamacare unlawful.

“Congress declared in the text of the law that the individual mandate is the centerpiece of Obamacare,” Paxton said in a statement, adding:

Without the unlawful mandate, the rest of the law cannot stand. Obamacare has failed, and the sooner it is invalidated, the sooner each state can decide what type of health care system will best provide for those with preexisting conditions, which is the way the Founders intended.

In December, the U.S. Court of Appeals for the Fifth Circuit in New Orleans ruled Obamacare’s individual mandate is unconstitutional.

“[T]he individual mandate is unconstitutional because it can no longer be read as a tax, and there is no other constitutional provision that justifies this exercise of congressional power,” the decision stated.

In the Trump administration’s brief, U.S. Solicitor General Noel J. Francisco noted that in 2012, “The Court upheld the mandate only by adopting a saving construction of 26 U.S.C. 5000A, characterizing the mandate as the predicate to a tax. But Congress has now eliminated the tax, removing the basis for that construction.”

He continued that nothing in the Tax Cuts and Jobs Act passed by Congress in 2017 “demonstrates it would have intended the rest of the ACA to continue to operate … The entire ACA thus must fall with the individual mandate.”