You may recall the circuit panel ruling in Halbig v. Burwell this past Summer. This is a little case with huge potential implications for the ACA. I say potential because the panel holding was quickly vacated by the DC Circuit Court of Appeals. This means that there is no split in the circuits at this time on whether the clear language of ACA limiting premium subsidies to individuals living in states with state-run exchanges will be upheld. Yes, the plaintiffs in Halbig are arguing that the language of the ACA should be upheld.
Limiting the availability of exchange subsidies to individuals living in states with state run exchanges (as the ACA's language clearly provides) would eliminate the availability of subsidies for those several million people that have purchased policies with subsidies through the federal exchange. This would have a significant impact on the ACA, if not a deadly one. Halbig was significant because it would have created a split in the circuit courts on the issue, making it more likely that the Supreme Court of the United States (SCOTUS) would take up the case. But when the panel decision was reversed, that split disappeared.
Yet, last week, SCOTUS agreed to hear an appeal from a different circuit court of appeal case considering the same issue: King v. Burwell.
Is that significant? All you need to grant cert at the Supreme Court is the vote of four justices. We do not know which four. We will have to wait for arguments this Spring and another ACA ruling this Summer.