A Wall Street Journal op-ed by former Reagan and Bush administration lawyers David Rivkin Jr. and Lee Casey launches another in a series of legally suspect attacks on the constitutionality of the Affordable Care Act. But this new challenge to the constitutionality of the individual mandate, based on the Constitution's “Uniformity Clause,” is so fanciful that even other conservative media question its validity.

Conceding that their argument has been “rarely considered,” Rivkin and Casey nonetheless claim that because Roberts upheld the individual mandate under Congress' power to tax, it is now subject to the “Uniformity Clause,” which requires the tax to “be uniform throughout the United States” :

[B]y transforming the mandate into a tax to avoid one set of constitutional problems (Congress having exceeded its constitutionally enumerated powers), the court has created another problem. If the mandate is an indirect tax, as the Supreme Court held, then the Constitution's “Uniformity Clause” (Article I, Section 8, Clause 1) requires the tax to “be uniform throughout the United States.” [...] [Al]though the court has upheld as “uniform” taxes that affect states differently in practice, precedent makes clear that a permissible tax must “operate with the same force and effect in every place where the subject of it is found,” as held in the Head Money Cases (1884). The ObamaCare tax arguably does not meet this standard. ObamaCare provides that low-income taxpayers, who are nevertheless above the federal poverty line, can discharge their mandate-tax obligation by enrolling in the new, expanded Medicaid program, which serves as the functional equivalent of a tax credit. But that program will not now exist in every state because, as a matter of federal law, states can opt out. The actual tax burden will not be geographically uniform as the court's precedents require.

But Rivkin and Casey neglect to mention that their argument has in fact been considered and rejected more than once since 1884. The Congressional Research Service concluded the argument presented “no constitutional issue” because the individual mandate would “satisfy the requirement of uniformity...on its face,” pursuant to the more recent case of United States v. Ptasynski. That 1983 Supreme Court decision held that “it was settled fairly early that the [Uniformity] Clause does not require Congress to devise a tax that falls equally or proportionately on each State.” Quoting from yet another Supreme Court opinion, Ptasynski further observed that "[t]he uniformity provision does not deny Congress the power to take into account differences that exist between different parts of the country, and to fashion legislation to resolve geographically isolated problems." As such:

Where Congress defines the subject of a tax in nongeographic terms, the Uniformity Clause is satisfied. See Knowlton v. Moore, 178 U.S. at 178 U. S. 106. We cannot say that, when Congress uses geographic terms to identify the same subject, the classification is invalidated. The Uniformity Clause gives Congress wide latitude in deciding what to tax and does not prohibit it from considering geographically isolated problems.

The National Review Online's Matthew Franck also found Rivkin and Casey's arguments unconvincing, noting that they did not consider (or quote) the rest of the 1884 Supreme Court case they cited:

But it's not at all clear that the choice of a state to opt out of a program that would make the alternative to paying the tax cheaper, or relieve affected persons of the taxpaying obligation altogether, renders the federal tax geographically non-uniform for constitutional purposes. All persons similarly situated-unable or unwilling to purchase health insurance, while obligated either to do so or to pay a tax-will be subject to the tax. The reasons for their being subject to the tax may be partly in the power of the state governments where they live-and the authority of states to make a choice that costs them something may itself be authorized by federal law-but that does not necessarily mean that the federal government has used its taxing power in a non-uniform manner. In the Head Money ruling itself, the Court held that the tax in question (if it really was a tax, and not an exercise of the commerce power-oh, how the world turns), a 50-cent charge on foreign passengers entering the country at American seaports, was not invalid by virtue of its not applying to foreigners entering the country over land by rail. "[T]he law applies to all ports alike," the Court observed, and added: “Perfect uniformity and perfect equality of taxation, in all the aspects in which the human mind can view it, is a baseless dream, as this court has said more than once.”

Despite the apparent holes in Rivkin and Casey's arguments, supporters of the Affordable Care Act should not ignore them. Rivkin has a notable track record in moving off-the-wall legal arguments into the political mainstream, as he was among the first to suggest - similarly without any support in existing law -- that the individual mandate might be unconstitutional under the Commerce Clause.