When Congress enacted President Donald Trump’s landmark tax reform plan in December, one media outlet proclaimed: “The GOP Tax Bill Kills Obamacare’s Individual Mandate.”

Turns out, the headline was wrong. The individual mandate—the unconstitutional requirement that most Americans buy health insurance—remains in the law.

The headline should have proclaimed that the tax bill repealed the tax penalty associated with the mandate, thereby rendering every single word of Obamacare unconstitutional under the Supreme Court’s reasoning.

Back in 2012, the Supreme Court narrowly upheld the constitutionality of Obamacare in a 5-4 decision. Although the five justices in the majority searched the entire Constitution, the deciding vote—Chief Justice John Roberts—found only one basis for Congress’ authority to enact the individual mandate: the power to levy taxes.

In his opinion, Roberts said that while Obamacare’s mandate is best read as an unconstitutional requirement on Americans—which Congress has no authority to enact—its constitutionality could be salvaged as a “tax” because the mandate’s associated tax penalties raise “at least some revenue.” Roberts cited this raising of “some revenue” as being “the essential feature of any tax.”

Last year, Congress repealed the individual mandate tax penalty, leaving only the unconstitutional mandate. This change rendered the individual mandate unconstitutional under Roberts’ reasoning. After all, the mandate no longer raises “some revenue.”

And without the mandate, the rest of the law falls.

President Barack Obama and the leaders of Congress made it very clear at the time that the individual mandate is the core of Obamacare. Without it, Obamacare cannot function as Congress and the Obama administration intended.

The Obama administration even told the Supreme Court that key parts of Obamacare would be invalid without the mandate. In other words, you cannot constitutionally separate the mandate from Obamacare’s structure. If the individual mandate is now unconstitutional, the entire law must be struck down.

Texas and Wisconsin, joined by 20 states, filed a lawsuit in federal court earlier this month asking the federal courts to obey what the Supreme Court has already recognized and hold all of Obamacare unconstitutional.

Since its passage in 2009, Obamacare has been a colossal failure. It has not lowered premiums for most Americans, and it has not brought down the cost of health care. It has succeeded in imposing billions of dollars in costs on individuals and endangered America itself by far overstepping the bounds of the federal power set by our Constitution.

Everyone except many of the politicians in Washington, D.C., understands that the powers of the federal government are, as James Madison famously put it, “few and defined.” Plainly and simply, the federal government’s authority is strictly limited to the matters spelled out in the text of the Constitution.

The 10th Amendment reserves the authority to do anything and everything else exclusively to the states or to the American people. The Founders did not build our Constitution around federalism for the benefit of law professors and D.C. politicians. They build it to be a castle wall guarding the liberty of all Americans.

We bring this challenge to Obamacare because, as state attorneys general, we took an oath of office to uphold the rule of law and protect the rights of Americans from the unconstitutional, ever-expanding intrusion of the federal government.

Through our multi-state lawsuit, we hope to restore the rule of law to our health care markets. Then the president and Congress can pursue the health care reform it actually has the authority to enact.