Jacob Sullum

But, as Vinson notes, "everything changed in 1937," when the Court held that Congress can regulate purely intrastate activities if they have a "substantial effect" on interstate commerce. That doctrine has led the Court to uphold federal regulation of activities, including the cultivation of wheat and marijuana for personal consumption, that are only remotely and hypothetically related to interstate commerce.

Since 1937, the Court has rejected just two provisions of federal law on Commerce Clause grounds: a ban on gun possession in or near schools, which it overturned in 1995, and a civil remedy for victims of gender-motivated violence, which it overturned in 2000. Those decisions were based on the Court's reluctance to "pile inference upon inference" in a way that would leave no activity beyond the reach of the Commerce Clause, thereby erasing the constitutional distinction between state and federal powers.

But as Justice Clarence Thomas noted in both cases, that danger will persist until the Supreme Court revisits the "substantial effects" doctrine. "By continuing to apply this rootless and malleable standard," he warned in 2000, "the Court has encouraged the federal government to persist in its view that the Commerce Clause has virtually no limits."

Despite the apoplectic reaction to Vinson's ruling from ObamaCare's supporters, the Supreme Court will leave this situation essentially unchanged if it ultimately endorses his reasoning. If it does not, an instrument of free trade will be converted into an instrument of compulsory transactions limited only by the imaginations of meddlesome legislators.

Jacob Sullum

Jacob Sullum is a senior editor at Reason magazine and a contributing columnist on Townhall.com.
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