That is the question that Robert Pear's article in yesterday's New York Times takes up. As Pear points out, President Obama (back in September 2009) vigorously defended ACA sec. 1501 as imposing a "penalty" for the failure to acquire health insurance -- no doubt to protect the Act from the charge that it was imposing a new tax on the middle class. But the Justice Department (as well as its amici) has defended the "minimum coverage provision," in both the Virginia and Florida lawsuits, as a valid exercise of Congress's taxing power (which derives from the General Welfare Clause of Article I, sec. 8, clause 1). As Jack Balkin has complained, the President “has not been honest with the American people about the nature of this bill. . . . This bill is a tax.” Balkin adds that, because it is a tax, it is "plainly constitutional."
Politically, the distinction between a penalty and a tax seems to matter. Legally, it is unclear that it does; the Supreme Court, at least since 1937, has typically only examined the form of the provision, and asked whether it raised any revenue at all. If so, it qualifies as a tax -- regardless of Congress's true purposes. But one of the fascinating questions in this litigation is whether the Supreme Court might be interested in revisiting this doctrinal point. Might five justices be willing to inquire into the intent of Congress in deciding whether a statutory provision constitutes a tax or a regulation for purposes of Article I? And if so, what would be the criteria for distinguishing the two?
Randy Barnett -- co-author of the CATO et al. amicus brief in the Virginia case and author of several pieces arguing that the individual mandate is unconstitutional -- discusses the significance of the article (and what it reveals about the true nature of ACA 1501) here at The Volokh Conspiracy.