It’s always dangerous to try to predict the outcome of a Supreme Court case, but after a spirited oral argument on Tuesday, the Affordable Care Act looks likely to survive its latest challenge. That shouldn’t be surprising given that this case, known as California v. Texas, is widely considered to be the weakest of the three existential challenges to the law to reach the court this decade.

You can read more background on the case here, but in short, the law is being challenged by a coalition of Republican attorneys general, governors, and two individuals — with the support of the Trump administration. They argue that when Congress set the penalty for not buying health insurance — known as the individual mandate — to $0 in 2017, it rendered the mandate unconstitutional. Without the mandate, they argue the entire law must also fall. 

During oral argument, a clear majority of justices suggested that the Affordable Care Act should not be struck down even if the mandate is unconstitutional. Chief Justice John Roberts noted that it’s hard “to argue that Congress intended the entire Act to fall if the mandate were struck down when the same Congress that lowered the penalty to zero did not even try to repeal the rest of the Act. I think, frankly, that they wanted the Court to do that. But that’s not our job.”

Justice Brett Kavanaugh appeared to agree with the U.S. House of Representatives (which intervened to defend the law alongside a coalition of Democratic attorneys general and governors led by California) that “this is a very straightforward case … that we would excise the mandate and leave the rest of the Act in place.”

It was more challenging to assess the other two issues at stake — whether the Republican states and two individuals had standing to sue in the first place and whether the mandate, with a $0 penalty, is now unconstitutional. Several justices did seem troubled by the weaknesses of the plaintiffs’ standing arguments, and some suggested the mandate might now be unconstitutional. This Health Affairs post provides an even deeper dive on the oral argument for the wonks among us.

As I discussed on Tradeoffs last week, the Supreme Court could rule in a number of ways. Even if a majority of justices conclude that the challengers have standing and the mandate is unconstitutional, their comments and questions on severability suggest that the rest of the Affordable Care Act — and with it health insurance for millions of people and the law’s many changes to Medicare, Medicaid, the Food and Drug Administration, the public health system and more — will be upheld. A final decision is expected by June 2021.

Katie Keith provides rapid response analysis of all things Affordable Care Act for Health Affairs’ “Following the ACA” blog. She also teaches courses on the ACA and LGBT health law and policy at Georgetown University Law Center and maintains a faculty appointment at the Georgetown Center on Health Insurance Reforms.