Twenty states are suing the Trump administration over the individual mandate in Obamacare that obligates people have health insurance or pay a fine, seeking an end to the entire law.

In the lawsuit filed Monday, states said Congress's decision to repeal the tax penalty as part of the Republican tax bill signed into law by President Trump, invalidates the mandate and all of Obamacare. The penalty still applies this year, but will go to zero beginning in 2019.

The complaint was filed in the U.S. District Court in the Northern District of Texas.

The Supreme Court upheld this portion of the law in 2012, determining it was allowed because it was a tax, and fit under the power of Congress to levy taxes.

The Obama administration had argued the individual mandate was allowed under Congress's power to regulate interstate commerce, a position the Supreme Court rejected. The ruling essentially concluded the federal government isn't allowed to force people who aren't engaged in commercial activities to buy a product or service they don't want.

"In reaching this end, the majority concluded that Congress’s taxing-power interpretation was only 'fairly possible' because the provision at issue raised 'at least some revenue for the Government,'" according to the complaint.

The Supreme Court's position on the taxing authority is now being used against the healthcare law, with Texas and Wisconsin leading the suit. Texas Attorney General Ken Paxton said the tax law has made the individual mandate unconstitutional because the penalty no longer applies, so it cannot be called a tax.

Plaintiffs argue the penalty was repealed — meaning the mandate doesn't carry a tax and does not raise government revenue — but the mandate to have health insurance remains written in law.

"With no remaining legitimate basis for the law, it is time that Americans are finally free from the stranglehold of Obamacare, once and for all," Paxton said in a statement.

The states noted in their lawsuit defenders of Obamacare argued the mandate was a necessary part of the law, saying some impetus was needed to bring healthier people into health insurance plans so they wouldn't need to turn away people with pre-existing illnesses like cancer or charge them more.

"Once the heart of the ACA — the individual mandate — is declared unconstitutional, the remainder of the ACA must also fall," the complaint reads.

Other than Maine and Mississippi, all of the states in the suit are represented by GOP attorneys general. Other states include Alabama, Arkansas, Arizona, Florida, Georgia, Indiana, Kansas, Louisiana, Missouri, Nebraska, North Dakota, South Carolina, South Dakota, Tennessee, Utah and West Virginia.

The Trump administration opposes Obamacare and supported repealing its tax, but may now be in a position to defend the law. Josh Blackman, a professor at South Texas College of Law, said on Twitter the Department of Justice would likely oppose the lawsuit on standing and other grounds.

"But does [Attorney General Jeff Sessions] submit a brief arguing that Obamacare is constitutional!? This case puts the Trump Administration in a really, really tough bind," he wrote.