A federal appeals court on Tuesday ruled that 16 Democratic state attorneys general may intervene in a lawsuit challenging subsidy payments to insurance companies under the Affordable Care Act (ACA). 

The lawsuit dates back to 2014 and the earliest days of the ACA, or Obamacare. In late 2014 several congressional Republicans sued to block the subsidies, arguing they were unconstitutional because Congress had not passed appropriations for them. The subsidies reportedly affect about 7 million people. They are a cost-sharing measure the federal government uses to help subsidize some co-pays and other insurance costs for people with low incomes covered under the ACA.

Tuesday’s ruling revives the lawsuit after it had lagged in the federal courts for years and comes just as Republicans in Congress attempted, and failed, to repeal Obamacare after seven years of railing against the health-care reform law. 

The ruling by the D.C. Circuit Court of Appeals both complicates those congressional efforts to undo or roll back Obamacare, especially the cost-sharing subsidies at issue in the lawsuit. The ruling also undermines threats made by President Trump to somehow cut off those subsidies altogether. 

In allowing the Democratic governors to intervene, the three-judge panel wrote that the states would be harmed if the subsidies ended. The court reasoned that ending the subsidies would result in more uninsured state residents, which would in turn shift health costs to public hospitals or force people to forego care altogether. The Department of Health and Human Services “nowhere argues in its intervention papers that it will adequately protect the States’ interests or even continue to prosecute the appeal,” according to the court.

New York Attorney General Eric Schneiderman called the decision “good news” for residents of his state in a statement following the release of the opinion. Schneiderman wrote in a tweet that if the president “cuts off vital subsidies under the #ACA, we will challenge it in court.”

“The court’s decision is good news for the hundreds of thousands of New York families that rely on these subsidies for their health care,” Schneiderman said in his statement. “It’s disturbingly clear that President Trump and his administration are willing to treat them as political pawns; but this coalition of attorneys general stands ready to defend these vital subsidies and the quality, affordable health care they ensure for millions of families across the country.”

The lawsuit will now proceed while Republicans in Congress continue efforts to undo Obamacare.