Congress is busily making plans for legislative action should the latest challenge to Obamacare prevail in the Supreme Court.

On Wednesday, the justices will hear arguments in King v. Burwell to decide whether the IRS had the authority to write a rule authorizing subsidies to go to millions of people in the 37 states with federal exchanges.

The plaintiffs say the language of the law is clear: Subsidies are allowed in “an Exchange established by the State under [section] 1311of the Patient Protection and Affordable Care Act.” It doesn’t just say this once, but nine times in various linguistic forms.

That is the point that MIT economist Jonathan Gruber made when he famously said: “If you’re a state, and you don’t set up an exchange, that means your citizens don’t get their tax credits.”