To tax, to spend, to regulate.

Introduction Two very different visions of the national government underpin the ongoing battle over the Affordable Care Act (1) (ACA). President Obama and supporters of the ACA believe in the power of government to protect individuals through regulation and collective action. (2) By contrast, the ACA's Republican and Tea Party opponents see expanded government as a fundamental threat to individual liberty and view the requirement that individuals purchase minimum health insurance (the so-called "individual mandate") as the conscription of the healthy to subsidize the sick. (3) This conflict over the federal government's proper role is, of course, not new; it has played out repeatedly over our nation's past. (4) But rarely since the New Deal has it surfaced in such a distinctly constitutional guise with respect to economic legislation. Instead, after the Supreme Court sustained broad congressional power seventy-plus years ago, (5) little doubt existed that the federal government generally had constitutional authority to regulate private activity if it chose to do so. The Rehnquist Court's reassertion of limits on congressional power under the Commerce Clause indicated that some measures may go too far. (6) Still, the fight over the federal government's proper role in the economic sphere has been largely political, not constitutional. National Federation of Independent Business v. Sebelius (7) (NFIB) challenged this basic constitutional consensus, with the most significant social welfare reform legislation in decades hanging in the balance. Moreover, reopening that constitutional consensus focused national attention on the Supreme Court, with perceptions of the Court as ideologically driven reinforced by the close association between the constitutional challenges to the ACA and conservative political views. (8) The country's obsession with the health care litigation provided a daily reminder of the extent to which the Court stood at the center of a political as well as a constitutional storm. Against this backdrop, it is hard not to see Chief Justice Roberts's opinion in NFIB as a consummate act of institutional diplomacy. Although at times writing for himself only, the Chief Justice's opinion determined the Court's path. He avoided the unpalatable result of having the Court invalidate President Obama's signature achievement in the midst of a close reelection campaign by a 5-4 vote that would have mapped the Justices' ideological leanings. In the process, he managed to offer something to everyone: liberals got the vast majority of the ACA upheld; (9) conservatives got new limits on Congress's regulatory and spending authority; (10) states not only got the freedom to refuse to expand their Medicaid programs without risk of losing funds, but also kept the ability to expand (with generous federal subsidies) if they want to. (11) Chief Justice Roberts even used the opinion as an opportunity to reassert the Court's preeminent role in enforcing the Constitution. (12) Reinforcing this institutionalist account are reports that his decision to uphold the mandate represented a change of heart after the initial conference. (13) We thus may have a second putative "switch in time" to protect the Court, three-quarters of a century after an earlier Justice Roberts is alleged to have done the same. (14) In short, the Chief Justice's opinion appears to be a jurisprudential compromise that allows the Court to straddle the rancorous political divide consuming the nation. At the same time, it has a legitimate legal basis. In upholding the mandate as a tax, Chief Justice Roberts acted in accordance with the Constitution's grant of a broad tax power, longstanding precedent, and the well-established presumption of constitutionality. But the Chief Jushandguns tice's approach created an opinion whose different parts stand in considerable analytic tension. His flat rejection of all applications of the mandate under the commerce power contrasts with his willingness to preserve as much of the ACA as possible under Congress's tax and spending authority. …