Opinion of the Court
refuse. That section provides that, if a State elects not to establish an Exchange, the Secretary "shall . . . establish and operate such Exchange within the State." 42 U. S. C. §18041(c)(1)(A). The whole point of that provision is to create a federal fallback in case a State chooses not to establish its own Exchange. Contrary to petitioners' argument, Congress did not believe it was offering States a deal they would not refuse—it expressly addressed what would happen if a State did refuse the deal.
C
Finally, the structure of Section 36B itself suggests that tax credits are not limited to State Exchanges. Section 36B(a) initially provides that tax credits "shall be allowed" for any "applicable taxpayer." Section 36B(c)(1) then defines an "applicable taxpayer" as someone who (among other things) has a household income between 100 percent and 400 percent of the federal poverty line. Together, these two provisions appear to make anyone in the specified income range eligible to receive a tax credit.
According to petitioners, however, those provisions are an empty promise in States with a Federal Exchange. In their view, an applicable taxpayer in such a State would be eligible for a tax credit—but the amount of that tax credit would always be zero. And that is because—diving several layers down into the Tax Code—Section 36B says that the amount of the tax credits shall be "an amount equal to the premium assistance credit amount," §36B(a); and then says that the term “premium assistance credit amount" means "the sum of the premium assistance amounts determined under paragraph (2) with respect to all coverage months of the taxpayer occurring during the taxable year," §36B(b)(1); and then says that the term "premium assistance amount" is tied to the amount of the monthly premium for insurance purchased on "an Exchange established by the State under [42 U. S. C.
