Regardless of the outcome of this case, all of the reforms required by the ACA will still be in effect. But without subsidies to keep costs low, these other reforms could create a death spiral of skyrocketing premiums that would collapse state health insurance markets. States, then, would face a choice: run your own health care exchange or risk a death spiral.

Justice Kennedy—a strong supporter of states’ rights and federalism—warned of the “serious constitutional problem” were the Court to take away subsidies from states with federally-run exchanges and leave them with such a fraught choice.