The Biden administration is telling the Supreme Court it believes the Affordable Care Act (ACA) -- or ObamaCare -- is constitutional, a reversal of the Trump Justice Department position.

The justices heard the arguments last fall in a case first brought by some red states challenging the ACA’s constitutionality -- and a decision is pending. But with the change of position, the high court could delay a ruling and order reargument in the case.

SUPREME COURT ALLOWS MORE CALIFORNIA CHURCHES TO CONDUCT INDOOR SERVICES, WITH SOME LIMITS

The Justice Department filed a letter Wednesday "to notify the Court that the United States no longer adheres to the conclusions in the previously filed brief." The health care case was argued a week after the election in November.

The Trump administration called on the justices to strike down the entire Obama-era health law under which some 23 million people get health insurance and millions more with preexisting health conditions are protected from discrimination.

The fight is over whether a 2017 change in a provision of the law known as the individual mandate rendered it unconstitutional. Congress eliminated the penalty for not having health insurance.

The Trump administration backed the view of Texas and other Republican-led states that if such an important part of the law is invalid, the entire law should fall with it.

In Wednesday's letter, the Justice Department said the now-toothless mandate remains constitutional, but that even if the court decides otherwise, the rest of the law should be left alone.

That outcome, rather than taking down the whole law, seemed a likely one based on the justices’ questions and comments in November.

LEFT-WING 'DARK MONEY' GROUPS PRESSURE DEMOCRATS TO KILL FILIBUSTER, PACK SUPREME COURT

President Joe Biden has called for strengthening the law, and he already has reopened sign-ups for people who might have lost their jobs and the health insurance that goes with them because of the coronavirus pandemic. He was vice president when the law was enacted in 2010.

This is the third major pending case at the Supreme Court in which Biden has differed with his predecessor. The other two are cases over President Donald Trump's push to build portions of the U.S.-Mexico border wall and a Trump policy forcing people seeking asylum to wait in Mexico for their hearings.

CLICK HERE TO GET THE FOX NEWS APP

The Biden Justice Department last month asked the justices to postpone arguments in two immigration cases. Oral arguments had been scheduled in the coming days, but the high court agreed to put off consideration of private challenges to Trump executive orders on using military funds to build the border wall and to enforce its "stay in Mexico" policy for asylum seekers.

The Associated Press contributed to this report.