This week, the Supreme Court hears oral arguments on the constitutionality of the 2010 health care overahaul’s “individual mandate,” which requires most Americans to purchase health insurance starting in 2014 or pay a monetary penalty.

The question is whether the individual mandate is within Congress’s power to regulate interstate commerce (“Commerce . . . among the several States”) or is “necessary and proper for carrying into Execution” that power.

It’s hard to see how the individual mandate is a regulation of interstate commerce. How can inactivity (not purchasing health insurance) in itself be considered commerce, let alone interstate commerce? And if it is, what’s to stop Congress from forcing us to purchase other goods and services from private companies?

For that reason, the outcome of the case should turn on whether the Administration can show that the individual mandate is both “necessary” and “proper” to carry into execution Congress’s power to regulate interstate commerce.

In making that argument, the Administration faces a dilemma – to meet the “necessary” test, it is forced to make legal arguments that fail the “proper” test.