Any hunt for the congressional intent behind a piece of legislation should start with the actual language of the law in question. And in this case, the language is unambiguous. Tax credits—that is, subsidies for health insurance—are limited to “Exchanges established by a State.” In case there was any confusion, the law defines “State” as “each of the 50 states plus the District of Columbia.” These qualifying exchanges must further be established under Section 1311 of the law, the section which deals with state-based exchanges. The federal exchanges are set up under the authority of a different section, 1321.

That’s it. That’s what the law says. That’s what Democratic members of Congress, in both the House and Senate, voted to pass, despite some initial disagreement over whether states or the federal government should be in charge of the exchanges. That’s the language that President Obama signed into effect.

Arguably, that should be the end of the debate. The language is clear and direct, and it is repeated several times. There isn’t really another plausible interpretation of the text in question.