The Affordable Care Act describes the “[s]hared responsibilitypayment” as a “penalty,” not a “tax.” That label is fatal to the application of the Anti-Injunction Act. It does not, however, control whether an exaction is within Congress’s power to tax. In answering that constitutional question, this Court follows a functional approach,“[d]isregarding the designation of the exaction, and viewing its substance and application.” United States v. Constantine, 296 U. S. 287, 294. Pp. 33–35.
Such an analysis suggests that the shared responsibility payment may for constitutional purposes be considered a tax. The payment is not so high that there is really no choice but to buy healthinsurance; the payment is not limited to willful violations, as penalties for unlawful acts often are; and the payment is collected solely by the IRS through the normal means of taxation. Cf. Bailey v. Drexel Furniture Co., 259 U. S. 20, 36–37. None of this is to say that payment is not intended to induce the purchase of health insurance. But the mandate need not be read to declare that failing to do so is unlawful. Neither the Affordable Care Act nor any other law attaches negative legal consequences to not buying health insurance, beyond requiring a payment to the IRS. And Congress’s choice of language—stating that individuals “shall” obtain insurance or pay a “penalty”—does not require reading §5000A as punishing unlawful conduct. It may also be read as imposing a tax on those who go without insurance. See New York v. United States, 505 U. S. 144, 169–174. Pp. 35–40.
Even if the mandate may reasonably be characterized as atax, it must still comply with the Direct Tax Clause, which provides: “No Capitation, or other direct, Tax shall be laid, unless in Proportion to the Census or Enumeration herein before directed to be taken.” Art. I, §9, cl. 4. A tax on going without health insurance is not like acapitation or other direct tax under this Court’s precedents. It therefore need not be apportioned so that each State pays in proportion toits population. Pp. 40–41.