During the 2009 debate over the health care law, President Obama insisted that the “shared responsibility payment” assessed on Americans who fail to obtain government-approved medical coverage is not a tax. “I absolutely reject that notion,” he toldABC’s George Stephanopoulos that September. “For us to say that you’ve got to take a responsibility to get health insurance is absolutely not a tax increase.”

After the law was enacted and challenged in court, the Obama administration changed its tune, arguing that the mandate is a legitimate exercise of the power to “lay and collect taxes.” That claim, which no court accepted until last week, contradicted the language of the statute and statements by members of Congress.

It even contradicted another argument the administration’s lawyers were making in the same case. The Anti-Injunction Act bars lawsuits “for the purpose of restraining the assessment or collection of any tax.” That meant that if the “shared responsibility payment” were deemed a tax, its opponents would not be able to challenge it until 2014, when it was scheduled to take effect. Preferring a quicker resolution, the Obama administration insisted that the payment, which it was simultaneously defending as a tax, was not a tax.

Roberts swallowed and regurgitated all of that illogic because, unlike the four dissenting justices, he was not prepared to overturn the health care law but, like them, could not accept the notion that forcing people to buy stuff counts as regulating interstate commerce. He warned that “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.”

But recasting regulation as taxation only magnifies this danger. Under the government’s view of the Commerce Clause, Roberts worried, Congress could order Americans to buy vegetables, citing the impact that poor diet has on health care costs. Under Roberts’ view of the tax power, Congress could do much the same thing, imposing a levy on people who fail to buy vegetables. It would not even have to allege a “substantial effect” on interstate commerce. Indeed, Roberts said “the breadth of Congress’s power to tax is greater than its power to regulate commerce.”

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