Since 1824, the Supreme Court has sought to define the Commerce Clause, at times expanding and at others limiting Congress' power under it. But as Buchanan Ingersoll & Rooney Litigation shareholder David J. Porter explained in an op-ed to the Pittsburgh Post-Gazette, a Commerce Clause defense of the controversial Patient Protection and Affordable Care Act is unprecedented – and unconstitutional.

In oral argument before the Supreme Court, the federal government defended the Act by asserting "that every person is an 'actuarial reality' whose current existence and eventual mortality creates a statistically measurable insurance risk," Porter explained.

Read the full op-ed"Strike It Down," (March 25, 2012)

"By that theory, everyone is inescapably a 'participant' in the health insurance market and therefore subject to federal regulation," the op-ed concluded. "Such metaphysical abstraction threatens not merely to further stretch, but finally to break the Framers' structural design that for 225 years has preserved individual liberty and served as a check on unlimited federal power."

But it hasn't always been that way.

"At the time the Constitution was ratified, 'commerce' referred to trade – buying and selling products," Porter wrote in the article. "[I]t did not include all economic activity, such as manufacturing, agriculture and labor."

A series of Supreme Court cases, beginning with Gibbons v. Ogden in 1824, redefined the Commerce Clause. In Gibbons, "the Court held that Congress may regulate interstate commerce, but not commerce that doesn't extend to or affect other states," Porter explained.

According to Porter, the 1942 Wickard v. Filburn decision is "generally considered the most expansive Commerce Clause decision to date." He elaborated –

In that case, the Court held that Congress could regulate a farmer's production and consumption of homegrown wheat because even though his activity was local, was not commerce and did not substantially or directly affect interstate commerce, it could, in combination with others' similar conduct, affect interstate commerce.

The Wickard decision is being tied closely to the Patient Protection and Affordable Care Act, which is now before the Supreme Court.

Porter noted the question at hand – "whether Congress has the power to compel non-participants into the health insurance market, so that they can then be regulated" – is a novel one with no precedent to govern the Court's decision.

Note: Originally published by the Pittsburgh Post-Gazette, Porter's article also appeared in 14 other media outlets.