All this action will tax the internet servers, but not for inactivity.
Roberts specifically offers an example of taxing 'inactivity' that he claims would pass muster:
An example may help illustrate why labels should not control here. Suppose Congress enacted a statute providing that every taxpayer who owns a house without energy efficient windows must pay $50 to the IRS. The amount due is adjusted based on factors such as taxable income and joint filing status, and is paid along with the taxpayer’s income tax return. Those whose income is below the filing threshold need not pay. The required payment is not called a “tax,”a “penalty,” or anything else. No one would doubt that this law imposed a tax, and was within Congress’s power to tax. That conclusion should not change simply because Congress used the word “penalty” to describe the payment. Interpreting such a law to be a tax would hardly “[i]mpos[e] a tax through judicial legislation.” Post, at 25. Rather, it would give practical effect to the Legislature’s enactment.
A bit later he tackles the apparent paradox that Congress cannot regulate inactivity but can tax it:
There may, however, be a more fundamental objection to a tax on those who lack health insurance. Even if onlya tax, the payment under §5000A(b) remains a burden that the Federal Government imposes for an omission, not an act. If it is troubling to interpret the Commerce Clause as authorizing Congress to regulate those who abstainfrom commerce, perhaps it should be similarly troubling topermit Congress to impose a tax for not doing something.
Three considerations allay this concern. First, and most importantly, it is abundantly clear the Constitution does not guarantee that individuals may avoid taxation throughinactivity. A capitation, after all, is a tax that everyone must pay simply for existing, and capitations are expressly contemplated by the Constitution. The Court today holds that our Constitution protects us from federal regulation under the Commerce Clause so long as we abstain from the regulated activity. But from its creation, the Constitution has made no such promise with respect to taxes. See Letter from Benjamin Franklin to M. Le Roy (Nov. 13, 1789) (“Our new Constitution is now established . . . but in this world nothing can be said to be certain,except death and taxes”).
Whether the mandate can be upheld under the Commerce Clause is a question about the scope of federal authority. Its answer depends on whether Congress can exercise what all acknowledge to be the novel course of directing individuals to purchase insurance. Congress’suse of the Taxing Clause to encourage buying something is, by contrast, not new. Tax incentives already promote, for example, purchasing homes and professional educations. See 26 U. S. C. §§163(h), 25A. Sustaining the mandate as a tax depends only on whether Congress has properly exercised its taxing power to encourage purchasing health insurance, not whether it can. Upholding the individual mandate under the Taxing Clause thus does not recognize any new federal power. It determines that Congress has used an existing one.
Second, Congress’s ability to use its taxing power toinfluence conduct is not without limits. A few of our cases policed these limits aggressively, invalidating punitive exactions obviously designed to regulate behavior otherwise regarded at the time as beyond federal authority.See, e.g., United States v. Butler, 297 U. S. 1 (1936); Drexel Furniture, 259 U. S. 20. More often and more recently we have declined to closely examine the regulatory motiveor effect of revenue-raising measures. See Kahriger, 345
U. S., at 27–31 (collecting cases). We have nonetheless maintained that “‘there comes a time in the extension of the penalizing features of the so-called tax when it loses its character as such and becomes a mere penalty with the characteristics of regulation and punishment.’” Kurth Ranch, 511 U. S., at 779 (quoting Drexel Furniture, supra, at 38).
We have already explained that the shared responsibility payment’s practical characteristics pass muster as atax under our narrowest interpretations of the taxing power. Supra, at 35–36. Because the tax at hand is within even those strict limits, we need not here decide the precise point at which an exaction becomes so punitivethat the taxing power does not authorize it. It remains true, however, that the “‘power to tax is not the power to destroy while this Court sits.’” Oklahoma Tax Comm’n v. Texas Co., 336 U. S. 342, 364 (1949) (quoting Panhandle Oil Co. v. Mississippi ex rel. Knox, 277 U. S. 218, 223 (1928) (Holmes, J., dissenting)).
Third, although the breadth of Congress’s power to taxis greater than its power to regulate commerce, the taxingpower does not give Congress the same degree of controlover individual behavior. Once we recognize that Congress may regulate a particular decision under the Commerce Clause, the Federal Government can bring its full weight to bear. Congress may simply command individuals to do as it directs. An individual who disobeys may be subjected to criminal sanctions. Those sanctions can include not only fines and imprisonment, but all the attendant consequences of being branded a criminal: deprivation of otherwise protected civil rights, such as the right to bear arms or vote in elections; loss of employment opportunities; social stigma; and severe disabilities in other controversies, such as custody or immigration disputes.
By contrast, Congress’s authority under the taxing power is limited to requiring an individual to pay money into the Federal Treasury, no more. If a tax is properly paid, the Government has no power to compel or punish individuals subject to it.
The Federal Government does not have the power toorder people to buy health insurance. Section 5000A would therefore be unconstitutional if read as a command. The Federal Government does have the power to impose atax on those without health insurance. Section 5000A is therefore constitutional, because it can reasonably be read as a tax.
I DON'T WANT TO READ ON: Scalia, Thomas, Alito and Kennedy join the dissent calling for the overturn of the whole act. But wait! Per the Volokh rumor mill, this "dissent" started out as the majority opinion until Roberts jumped ship over the tax argument. The key evidence is that in the Scalia dissent he refers to the Ginsburg "dissent", even though she was in the majority (p 139 .pdf):
A few respectful responses to JUSTICE GINSBURG’s dissent on the issue of the Mandate are in order...
Hmm, they say their response is respectful but I am not sure they meant it:
The dissent’s exposition of the wonderful things the Federal Government has achieved through exercise of its assigned powers, such as “the provision of old-age and survivors’ benefits” in the Social Security Act, ante, at 2, is quite beside the point. The issue here is whether the federal government can impose the Individual Mandate through the Commerce Clause. And the relevant history is not that Congress has achieved wide and wonderful results through the proper exercise of its assigned powers in the past, but that it has never before used the Commerce Clause to compel entry into commerce.3 The dissent treats the Constitution as though it is an enumeration of those problems that the Federal Government can address—among which, it finds, is “the Nation’s course in the economic and social welfare realm,” ibid., and more specifically “the problem of the uninsured,” ante, at 7. The Constitution is not that. It enumerates not federally soluble problems, but federally available powers. The Federal Government can address whatever problems it wants but can bring to their solution only those powers that the Constitution confers, among which is the power to regulate commerce. None of our cases say anything else. Article I contains no whatever-it-takes-to-solve-a-national problem power.
USELESS WAVE OF NOSTALGIA: Here is the text of Obama explaining to George S that the mandate is not, nay, no never a tax. Steve Benen provides the pom poms on the left.