Does the Patient Protection and Affordable Care Act (ACA) of 2010 authorize tax credits within the thirty-six states that failed to establish health insurance exchanges? That is the question presented in Pruitt v. Burwell, Halbig v. Burwell, King v. Burwell, and Indiana v. IRS. The plaintiffs argue that the statute is clear and forecloses any possibility of tax credits in federal exchanges. The government argues that the statute plainly authorizes tax credits in federal exchanges, or is at least ambiguous on the question. Mere disagreement is not evidence of ambiguity. Reaching the truth requires wading deep into each side’s arguments. Whether the relevant text is viewed in isolation or in its full statutory context, the ACA only authorizes tax credits in exchanges established by the states.