Those of us eagerly awaiting the outcome of King v Burwell had our answer from a single innocuous word in the first sentence of the decision, when the majority describes the reforms as “interlocking.”

The health reform package Congress passed in 2010 is complex, the product of a series of political compromises. A thousand-page statute reflects that complexity. The Patient Protection and Affordable Care Act (ACA) lives to fight another day because a majority of the Court was willing to look past some sloppily-worded language in the tome and grapple with what the reforms as a whole aimed to achieve.

King centered on one provision, section 36B, which, on its face, appears to limit the circumstances in which people who buy health insurance can get financial assistance from the federal government. The language of the provision, according to the challengers’ argument, does not allow poor and near-poor purchasers to receive subsidies in states that have not established their own health insurance “exchanges” (the apparatus established by the ACA to link buyers with sellers). Since 34 states passed on the opportunity to establish their own exchanges, and more than 6 million people in those states are eligible for subsidies to make their health insurance affordable, accepting the challengers’ interpretation would have been a devastating blow to the viability of the reforms.

Both the majority and dissenting decisions wind their way through technical exercises in statutory interpretation. Both carefully dissect section 36B. Both summon precedent to guide their analysis, and both cross-reference other provisions in the Act to help elucidate meaning and intent. But the majority is prepared to travel down a road the dissenters won’t. In searching for Congressional intent, the majority widens its frame to consider the broader rationale, structure, and functioning of the reforms Congress passed.

The majority reviews the history and logic of the three-legged stool on which the reform package sits: (1) rules that stop insurers refusing coverage or jacking up premiums for the sick; (2) a requirement that individuals buy insurance; and (3) financial assistance in the form of tax subsidies to help poor families comply with the purchase mandate. The majority recognizes that restricting subsidies to state exchanges effectively kicks out the third leg, and means the stool will probably topple. The unhappy experiences of a few states with one- and two-legged reforms are reviewed; there is also mention of a couple of health services research studies that presage an unraveling. After tracking through the rationale for the architecture of the reforms, the majority finds it “implausible” that Congress could have intended the interpretation urged by the petitioners.

Along the way, the Court observes that “key parts of the Act were written behind closed doors.” Congress passed the Act by turning to “a complicated budgetary procedure. . . which limited opportunities for debate and amendment.” The product is described as an Act that “does not reflect the type of care and deliberation that one might expect of such significant legislation.” It is difficult to tell if this is a hand slap for one side of the aisle, or an acknowledgement of the unavoidable chaos that surrounds birthing an ambitious, sprawling social reform in a time of deeply partisan politics.

Five years ago, shortly after the ACA had been signed into law but before the major challenges had materialized, I had an opportunity to talk to Chief Justice Roberts about the challenges that would inevitably be coming to his doorstep. I asked how much his Court will care about the health policy implications of its rulings. His response was what you might expect from a politically astute jurist. That was not their concern, he said; the Court’s job was to stick to interpreting the law and avoid policy analysis.

The Court would have had to strain very hard to maintain that separation in King v Burwell. The case invited the Court to understand and weigh the wider health policy implications of alternative interpretations of a crucial clause in the ACA. Six of the nine justices took up the invitation, and proceeded to show an impressive command of why the federal reforms were introduced and how the cogs in the clock work together. A willingness to seriously engage with these details spelled the end of the challenge. In many ways, the rest is legal garnish.