One criticism of originalism in constitutional law is that we cannot always determine with reasonable certainty what the Framers of the 1787 Constitution, the Bill of Rights, or the Fourteenth Amendment intended or what the public understood those provisions to mean. Nonsense, say defenders of originalism. There is plenty of evidence on what the Constitution meant, and even where there is less we can still pull enough together to give courts guidance.
Halbig pokes a hole in this argument. At issue is a major provision in the most visible statute passed by Congress in years (if not decades). And we cannot agree what that provision was trying to accomplish just four years after it was enacted. Did Congress use subsidies to give states an incentive to set up health insurance exchanges, or was that not the case? Was there a drafting error, or was this intentional? If that is unknowable, what are we supposed to do with ambiguous constitutional provisions ratified more than two centuries ago?