In NFIB v. Sebelius, Congress had enacted the Affordable Care Act, in which individual persons were required to buy health insurance from a private company. The statute referred to a requirement that people buy health insurance that was enforced by a penalty if they should fail to do so. The question was whether this was within Congress's commerce power. So NFIB v. Sebelius is not really a Commerce Clause case. In the 1940s, the Supreme Court had held that the regulation of the insurance business was part of Congress's commerce power, and that was not an issue in the case. What was an issue in the case is whether it was necessary and proper for Congress to command American citizens to do business with private insurance companies. The real issue in NFIB v. Sebelius was whether making individuals do business with a private company through use of so-called purchase mandates was a proper exercise of federal power. Five justices agreed with the challengers that this was not a proper exercise of federal power. A requirement that you buy insurance from a private company was an improper exercise of Congress's power under the Necessary and Proper Clause and its Commerce Clause power, but one of those five adopted what he called a saving construction to change the requirement to buy health insurance enforced by a penalty into, in effect, an option to either buy insurance or pay a modest and non- coercive tax. This way it was not a purchase mandate that was upheld. It was an option to buy insurance or pay a non-coercive tax. Chief Justice Roberts said that if the tax were high enough to become coercive, then that would be a problem. But since it was low enough to not be coercive, then it was simply a tax and could be upheld. He said this was not the natural reading of the statute, but the courts had an obligation to defer to the statute, in his words, if there was a reasonably possible reading of the statute that would be constitutional. Because he concluded that a reasonably possible reading of the statute was an option to buy insurance or pay a non-coercive tax, he could uphold the Affordable Care Act. The biggest misconception of NFIB v. Sebelius is that it upheld the individual insurance mandate as a tax. It did not. It changed the individual insurance mandate into something that was not really a mandate at all. It was an option to buy insurance or pay a modest non-coercive tax. That's what was upheld in NFIB v. Sebelius.