In national federation of independent business v. sebelius (2012)the supreme court found that

Excerpt: Majority Opinion, Chief Justice Roberts

The individual mandate . . . does not regulate existing commercial activity. It instead compels individuals to become active in commerce by purchasing a product, on the ground that their failure to do so affects interstate commerce. Construing the Commerce Clause to permit Congress to regulate individuals precisely because they are doing nothing would open a new and potentially vast domain to congressional authority. Every day individuals do not do an infinite number of things. In some cases they decide not to do something; in others they simply fail to do it. Allowing Congress to justify federal regulation by pointing to the effect of inaction on commerce would bring countless decisions an individual could potentially make within the scope of federal regulation, and—under the Government’s theory—empower Congress to make those decisions for him. . . .

The Affordable Care Act is constitutional in part and unconstitutional in part. The individual mandate cannot be upheld as an exercise of Congress’s power under the Commerce Clause. That Clause authorizes Congress to regulate interstate commerce, not to order individuals to engage in it. In this case, however, it is reasonable to construe what Congress has done as increasing taxes on those who have a certain amount of income, but choose to go without health insurance. Such legislation is within Congress’s power to tax.

As for the Medicaid expansion, that portion of the Affordable Care Act violates the Constitution by threatening existing Medicaid funding. Congress has no authority to order the States to regulate according to its instructions. Congress may offer the States grants and require the States to comply with accompanying conditions, but the States must have a genuine choice whether to accept the offer. The States are given no such choice in this case: They must either accept a basic change in the nature of Medicaid, or risk losing all Medicaid funding. The remedy for that constitutional violation is to preclude the Federal Government from imposing such a sanction. That remedy does not require striking down other portions of the Affordable Care Act.

The Framers created a Federal Government of limited powers, and assigned to this Court the duty of enforcing those limits. The Court does so today. But the Court does not express any opinion on the wisdom of the Affordable Care Act. Under the Constitution, that judgment is reserved to the people.

Excerpt: Concurrence In Part and Dissent In Part, Justice Ruth Bader Ginsburg

The Commerce Clause, it is widely acknowledged, “was the Framers’ response to the central problem that gave rise to the Constitution itself.” . . . Under the Articles of Confederation, the Constitution’s precursor, the regulation of commerce was left to the States. This scheme proved unworkable, because the individual States, understandably focused on their own economic interests, often failed to take actions critical to the success of the Nation as a whole. . .

What was needed was a “national Government . . . armed with a positive & compleat authority in all cases where uniform measures are necessary.” See Letter from James Madison to Edmund Randolph . . . The Framers’ solution was the Commerce Clause, which, as they perceived it, granted Congress the authority to enact economic legislation “in all Cases for the general Interests of the Union, and also in those Cases to which the States are separately incompetent.” 2 Records of the Federal Convention of 1787 . . . .

The Framers understood that the “general Interests of the Union” would change over time, in ways they could not anticipate. Accordingly, they recognized that the Constitution was of necessity a “great outlin[e],” not a detailed blueprint . . . and that its provisions included broad concepts, to be “explained by the context or by the facts of the case,” Letter from James Madison to N. P. Trist . . . “Nothing . . . can be more fallacious,” Alexander Hamilton emphasized, “than to infer the extent of any power, proper to be lodged in the national government, from . . . its immediate necessities. There ought to be a capacity to provide for future contingencies[,] as they may happen; and as these are illimitable in their nature, it is impossible safely to limit that capacity.” . . .

[The] novel constraint on Congress’ commerce power gains no force from our precedent and for that reason alone warrants disapprobation. But even assuming, for the moment, that Congress lacks authority under the Commerce Clause to “compel individuals not engaged in commerce to purchase an unwanted product,” such a limitation would be inapplicable here. Everyone will, at some point, consume health-care products and services. Thus, if THE CHIEF JUSTICE is correct that an insurance-purchase requirement can be applied only to those who “actively” consume health care, the minimum coverage provision fits the bill.

THE CHIEF JUSTICE does not dispute that all U.S. residents participate in the market for health services over the course of their lives. . . .

When contemplated in its extreme, almost any power looks dangerous. The commerce power, hypothetically, would enable Congress to prohibit the purchase and home production of all meat, fish, and dairy goods, effectively compelling Americans to eat only vegetables. Yet no one would offer the “hypothetical and unreal possibilit[y]” of a vegetarian state as a credible reason to deny Congress the authority ever to ban the possession and sale of goods. . . .

For decades, the Court has declined to override legislation because of its novelty, and for good reason. As our national economy grows and changes, we have recognized, Congress must adapt to the changing “economic and financial realities.” Hindering Congress’ ability to do so is shortsighted; if history is any guide, today’s constriction of the Commerce Clause will not endure. . . .

Medicaid, as amended by the ACA, . . .is not two spending programs; it is a single program with a constant aim—to enable poor persons to receive basic health care when they need it. Given past expansions, plus express statutory warning that Congress may change the requirements participating States must meet, there can be no tenable claim that the ACA fails for lack of notice. Moreover, States have no entitlement to receive any Medicaid funds; they enjoy only the opportunity to accept funds on Congress’ terms. Future Congresses are not bound by their predecessors’ dispositions; they have authority to spend federal revenue as they see fit. The Federal Government, therefore, is not . . . threatening States with the loss of “existing” funds from one spending program in order to induce them to opt into another program. Congress is simply requiring States to do what States have long been required to do to receive Medicaid funding: comply with the conditions Congress prescribes for participation.

Excerpt: Joint Dissent, Justices Antonin Scalia, Anthony Kennedy, Clarence Thomas, and Samuel Alito

This case is in one respect difficult: It presents two questions of first impression. The first of those is whether failure to engage in economic activity (the purchase of health insurance) is subject to regulation under the Commerce Clause. Failure to act does result in an effect on commerce, and hence might be said to come under this Court’s “affecting commerce” criterion of Commerce Clause jurisprudence. But in none of its decisions has this Court extended the Clause that far. The second question is whether the congressional power to tax and spend, U.S. Const., Art. I, § 8, cl. 1, permits the conditioning of a State’s continued receipt of all funds under a massive state-administered federal welfare program upon its acceptance of an expansion to that program. Several of our opinions have suggested that the power to tax and spend cannot be used to coerce state administration of a federal program, but we have never found a law enacted under the spending power to be coercive. Those questions are difficult. . . .

Whatever may be the conceptual limits upon the Commerce Clause and upon the power to tax and spend, they cannot be such as will enable the Federal Government to regulate all private conduct and to compel the States to function as administrators of federal programs.

That clear principle carries the day here. The striking case of Wickard v. Filburn, which held that the economic activity of growing wheat, even for one’s own consumption, affected commerce sufficiently that it could be regulated, always has been regarded as the ne plus ultra of expansive Commerce Clause jurisprudence. To go beyond that, and to say the failure to grow wheat (which is not an economic activity, or any activity at all) nonetheless affects commerce and therefore can be federally regulated, is to make mere breathing in and out the basis for federal prescription and to extend federal power to virtually all human activity. . . .

As for the constitutional power to tax and spend for the general welfare: The Court has long since expanded that beyond (what Madison thought it meant) taxing and spending for those aspects of the general welfare that were within the Federal Government’s enumerated powers. . . . The principal practical obstacle that prevents Congress from using the tax-and-spend power to assume all the general-welfare responsibilities traditionally exercised by the States is the sheer impossibility of managing a Federal Government large enough to administer such a system. That obstacle can be overcome by granting funds to the States, allowing them to administer the program. That is fair and constitutional enough when the States freely agree to have their powers employed and their employees enlisted in the federal scheme. But it is a blatant violation of the constitutional structure when the States have no choice. . . .

Our cases establish a clear line between a tax and a penalty: “‘[A] tax is an enforced contribution to provide for the support of government; a penalty ... is an exaction imposed by statute as punishment for an unlawful act.’” In a few cases, this Court has held that a “tax” imposed upon private conduct was so onerous as to be in effect a penalty. But we have never held—never—that a penalty imposed for violation of the law was so trivial as to be in effect a tax. We have never held that any exaction imposed for violation of the law is an exercise of Congress’ taxing power—even when the statute calls it a tax, much less when (as here) the statute repeatedly calls it a penalty. . . .