And while the US Court of Appeals in New Orleans that's handling the matter is known for its conservatism, Congress'decision in 2017 to remove the penalty for not having coverage means Texas and its allies could have problems proving any harm to give them grounds for their challenge.
That would put the issue firmly back in the hands of politicians, which threatens to hurt Republicans in 2020 as they revive their decade-long quest to gut the law without a viable replacement.
The healthcare filing could prove to be a gift for Democrats as they seek to refocus their messaging on issues important to voters.
The debate over Obamacare - which Republicans tried unsuccessfully to repeal in 2017 - caused heartburn for the party in the 2018 Midterm elections and was a focal point for Democrats on the campaign trail.
"Tonight in federal court, the Trump Administration decided not only to try to destroy protections for Americans living with pre-existing conditions, but to declare all-out war on the healthcare of the American people," House Speaker Nancy Pelosi said.
The move comes as the White House is celebrating Attorney-General William Barr's review of the long-awaited findings by Special Counsel Robert Mueller, which he reported didn't find evidence to show the Trump campaign conspired with Russia to meddle in the 2016 election.
Senate Minority Leader Chuck Schumer, a New York Democrat, said the Justice Department decision "will prove far more detrimental" to the Republicans than any political "gains" they might enjoy from the end of Mueller's investigation.
"The move by the Trump Administration is a slap in the face to American families," Schumer said Tuesday on the Senate floor.
Democratic strategist and campaign veteran Jesse Ferguson said Trump's party "lost the Midterms" as a result of its position on healthcare. Exit polls published by CNN found that healthcare was the top issue for 2018 voters in House elections across the country. The 41 per cent who cited it preferred Democratic candidates over Republicans by a jarring margin of 75 to 23 per cent.
Yet it's an issue Democrats have struggled to stay focused on after taking the House in January and effectively neutering the Republican threat to repeal the 2010 law. Trump's vow to repeal the law was a central promise of his 2016 campaign.
Democratic National Committee Tom Perez said the filing moves Republicans "one step closer to throwing the financial security and peace of mind of millions - not to mention one of the largest sectors of our economy - into a tailspin."
The Affordable Care Act has extended coverage to about 20 million Americans through private insurance marketplaces and an expansion of Medicaid. It has long been a target of conservatives for its tax hikes, regulations and new spending, which they argue have exacerbated the healthcare system.
Texas and its allied states assert that because Congress in 2017 zeroed out the tax penalty for violating Obamacare's individual mandate to buy insurance, the measure is no longer constitutional, and that the rest of the law is "inseverable" from it and "therefore invalid."
Several states, including California, New York, Illinois, Connecticut and Virginia have intervened in the suit to keep Obamacare intact.
- Bloomberg
