The taxing power argument by the Chief Justice is flawed in several ways. As the dissent noted, the Court should not have decided such an important case on grounds so lightly briefed and argued.
Essentially, the Court guts the Constitutional requirement that capitations be apportioned. If what would otherwise be a capitation has any exceptions or exemptions, it is not a capitation. That is so easily accomplished as to render meaningless what was a major issue at the Constitutional Convention. The Court latched onto broad language from one opinion in Hylton - a 216 year-old case - as if it were language from the Constitution. Essentially, a capitation applies if it applies to everyone, without exception. If so, then a Capitation is, by definition, apportioned. Thus, the Court reads "apportionment" as redundant. That is not correct.
The Court ignores the uniformity requirement for excises, duties, and imposts, as well as the "derived" requirement for income taxes. It never describes this "tax" as an excise, a duty, an impost, or an income tax. Instead, it merely describes it as a non-direct tax.
Some have argued over the past two-hundred years that Congress might have the power to enact some other type of tax. Well, here it is, without comment as to the Constitutional language, without comment distinguishing the new "tax" from traditional income taxes, excises, duties or imposts - and with almost flippant disregard for apportionment, which formed the basis for the three-fifths compromise. Regardless of the controversial nature of the three-fifths compromise (counting slaves as three-fifths of a person for representation and tax apportionment), we likely would not have had the Constitution without the compromise. We would not have had the compromise with the requirement of apportionment. Thus, without the apportionment requirement, we would likely not have had a Constitution; but, the Court acts as if it means nothing.
The dissent was correct: The Court should not have decided on such grounds without adequate briefs and argument. The majority arguments could easily have been addressed in lower courts or in brief or at argument. This was rushed and creates bad law. It will not likely stand if Congress chooses to use this newly found taxing power again: to tax inactivity by some but not all persons.
I like that the commerce power cannot be used to compel activity. I like that necessary and proper does not grant powers not otherwise enumerated. I take some solace in that a new tax is unlikely to gain much political support in the foreseeable future; hence, this great expansion of Congressional power (and unfortunate gutting of a critical Constitutional limitation, i.e., apportionment) is less troubling than an expansion of commerce power would have been.