Members of Congress who want to repeal laws that pledge government payments must do more than simply strip the funding for that law during the appropriations process, the Supreme Court reiterated in a Monday opinion.

The justices dove back into the limits of appropriations riders that don’t repeal a law expressly — and instead only repeal a law by implication — in a legal fight over about $12 billion in government payments to health insurance companies as part of a key program in the 2010 health care law.

One part of President Barack Obama’s signature law — which has been a legal and political battleground since its signing — set up a three-year “Risk Corridors” program to ease the transition into a new online health insurance market. It included a formula to determine the government’s obligation to pay insurers who lost money and did not limit the amount it might pay.

But the government argued that congressional Republicans inserted appropriations riders in a December 2014 spending bill that essentially stopped those payments by limiting funding. The resulting court fights have lasted for years.

On Monday, the justices looked at the health care law known as the Affordable Care Act, the language of this particular appropriations rider, a floor speech, other government action, and previous Supreme Court cases going back to 1886 to conclude that “an implied-repeal-by-rider must be made of sterner stuff.”

The opinion has one main theme: The wording of appropriations riders matters.

The 2014 spending bill riders didn’t reference or change the Risk Corridor program’s payment formula, the opinion states. The riders did not use a kind of “shall not take effect” language that had caused the Supreme Court in 1980 to find Congress had used an appropriations process to cancel obligations for pay raises.

And the 2014 riders limited funding by using the phrase, “None of the funds made available by this Act.” The Supreme Court compared that to other riders — even those in that same spending bill — that sought to repeal or suspend a law by using a more encompassing phrase: “None of the funds appropriated or otherwise made available by this or any other Act shall be used.”

In sum, the Supreme Court found that no words were used to indicate any other purpose than disbursement of funds for the particular fiscal year.

“Congress could have used the kind of language we have held to effect a repeal or suspension — indeed, it did so in other provisions of the relevant appropriations bills,” the Supreme Court ruled. “But for the Risk Corridors program, it did not.”

The majority opinion also was not swayed by a statement from Kentucky Republican Rep. Harold Rogers — which Congress later adopted as an “explanatory statement” — that the rider meant the government would be budget neutral and not pay out more than it collected through the program.

Because the program did not collect as much as it owed, it would essentially stop payments.

But the court said Rogers’ statement misunderstood a Department of Health and Human Services regulation that had only “projected” the program would be budget neutral and the agency “intended” to treat it that way.

The law did not require the Risk Corridors program to be budget neutral, and neither Rogers nor the appropriations rider said anything about requiring budget neutrality or redefining the law’s formula, the court wrote.