On the Supreme Court website, you can find the docket for this case (the title is National Federation of Independent Business v. Sebelius), which lists all the papers filed with the Court (this word is traditionally capitalized for the Supreme Court). It’s a long list. Oral argument is a dramatic high point, but it is only the tip of the iceberg in terms of the information provided to the Court.
The opinion begins with a “syllabus” by a Court official, the Reporter of Decisions. The syllabus summarizes the background of the case and the main issues resolved in the opinion. Note that there are multiple opinions and various justices have joined in different parts of those opinions. To figure out whether the Court’s has a “majority opinion” on any particular point, you must count how many justices sign (or concur in) a particular opinion part.
The PPACA is a complex law. Fortunately us, the Court focused chiefly at two provisions. The first is the “individual mandate” that requires everyone (with some exceptions) to purchase health insurance meeting various federal requirements or else pay a “shared responsibility payment” (let’s call it the “SRP”) to the federal government. (Note that in the following discussion I am not concerned with the wisdom of the PPACA, only with whether it is a valid enactment. This is (or should be) the Court’s approach as well.)
Before asking whether the individual mandate is a proper exercise of Congressional power, Chief Justice Roberts considers the federal Anti-Injunction Act, a law that prohibits challenging any tax before the challenger has actually paid it. Should the SRP be considered a tax? If so, then any court challenge is premature because no one has yet paid the SRP.
Chief Justice Roberts discusses this issue in part II of his opinion, concluding that the SRP is not a tax for purposes of the Anti-Injunction Act. His reasoning is straightforward: the PPACA contains several provisions that expressly impose taxes but the SRP is called a “penalty” and not a tax. The Chief Justice notes, “[w]here Congress uses certain language in one part of a statute and different language in another, it is generally presumed that Congress acts intentionally” and “the best evidence of Congress’s intent is the statutory text.” (These statements, it seems to me, reflect a judicial approach to acts of Congress that respects the equal status of the two branches.)
To make sure this issue was fully considered, the Court invited a senior lawyer (a “friend of the Court” or in Latin “amicus”) to submit a brief making the best arguments in favor of applying the Anti-Injunction Act. The amicus suggested that since the PPACA calls for the SRP to be “assessed and collected in the same manner” as taxes, this is evidence that the SRP is a tax. Chief Justice Roberts rejects this argument. To the contrary, he says, this provision actually supports the conclusion that the SRP is not a tax. If it were a tax, there would be no need to direct that it be assessed and collected in the same manner as taxes. It is because it is a penalty (and not a tax) that it makes sense to explain that the procedure for collecting it will be through the taxing authority.
Justices Ginsburg, Sotomayor, Breyer and Kagan agree with the Chief Justice’s conclusion in their separate opinion, and Justices Scalia, Thomas, Kennedy and Alito also agree in their dissent. So this part of the opinion is unanimous in result, if not in reasoning.