Congress passed the Affordable Care Act to improve health insurance markets, not to destroy them. If at all possible, we must interpret the Act in a way that is consistent with the former, and avoids the latter. Section 36B can fairly be read consistent with what we see as Congress’s plan, and that is the reading we adopt.
The full opinion, joined by 5 other justices, as well as Justice Scalia's dissent, joined by 2 other justices, is here.