Next week, the Supreme Court hears oral arguments on the constitutionality of the 2010 health care overhaul’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’ 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 the failure to purchase health insurance be considered commerce, let alone interstate commerce? If it is, what can’t Congress force us to purchase?

For that reason, the outcome of the case should turn on whether the Obama administration can show that the individual mandate is both “necessary” and “proper” to carry into execution Congress’ 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.

The administration relies on two legal theories to argue the individual mandate is “necessary”:

• Under an established Supreme Court doctrine, Congress may regulate activity that is neither interstate nor commerce if it “substantially affects interstate commerce.” The administration says the failure to purchase health insurance “substantially affects” interstate commerce because, in the aggregate, people without insurance don’t pay all of their medical costs and that causes higher insurance premiums for everyone.

• Under a theory proposed by Justice Antonin Scalia (but never adopted by the Supreme Court), Congress may regulate purely local activity that doesn’t substantially affect interstate commerce if it is “essential to a broader scheme to regulate interstate commerce.” The administration says the individual mandate meets that test because the health care reform law won’t work without it. (The reason has to do with requirements for insurers to cover pre-existing conditions and resulting incentives for people to forgo insurance until they are sick.)

If these legal theories justify the individual mandate, what are the outer limits of Congress’ commerce power? Can Congress force people to get checkups, purchase healthful foods, join a health club or even exercise on the theory that failing to do so increases medical costs and overall insurance premiums? Can Congress mandate other purchases or private conduct by adopting a permitted regulatory program that won’t work without a mandate and then imposing the mandate?

The administration tries to avoid these questions by saying health care is unique because it is inevitable, unpredictable and costly. But that isn’t a constitutional principle. And, in any event, it doesn’t prevent future intrusive health care mandates.

Assuming the individual mandate meets the “necessary” test, it must also meet the “proper” test, which the Supreme Court has said is satisfied only if a law is consistent with “the letter and spirit of the Constitution.”

On its face, the individual mandate fails that test.

• It abandons the long-standing legal principle that legally binding contracts require mutual assent and cannot be coerced. This crosses a line the federal government has never crossed and effectively tramples on “The powers … reserved … to the people” under the 10th Amendment.

• It is inconsistent with the fundamental concept of self-ownership that underlies the theory of natural rights in the Declaration of Independence — the idea that we own ourselves and, therefore, have the right to be left alone as long as we honor the equal right of others to be left alone.

Beyond that, the administration’s expansive view of the commerce power creates a sea of federal power limited only by islands of individual rights (and limits on using the commerce power to regulate noneconomic activity), and that is inconsistent with the letter and spirit of the Constitution:

• It imposes virtually the same limits on federal and state power and, therefore, effectively gives the federal government the same police powers as the states.

• It puts liberty at risk by relying entirely on individual rights to protect us against things such as mandated doctor visits and exercise. For example, the Supreme Court has found an unenumerated “right to liberty” only where there is no harm to others. The courts could easily decide that skipping annual physicals or living a sedentary life harms others by raising medical costs for some and insurance premiums for all.

The administration downplays the threat to liberty posed by the individual mandate by arguing:

• The federal government imposes mandates all the time. The reality: The only existing federal mandates are registration for military conscription, jury duty and census participation. These are all essential to the very existence of the federal government and therefore considered fundamental duties of citizenship.

• Mandates are no more intrusive than the regulation or prohibition of chosen activity. The reality: A dozen prohibitions of chosen activity leave you free to do an infinite number of things. A dozen mandates can potentially occupy all of your time and consume all of your financial resources.

• Congress can achieve the same thing through its taxing power, such as by imposing a tax and giving a rebate if the taxpayer purchases health insurance. The reality: That doesn’t mean Congress can use the commerce power to impose mandates, and because narrowly targeted mandates are politically easier to impose than broad-based tax increases, they are a greater threat to liberty.

Ultimately, the Obama administration’s arguments on the “necessary” test undermine its arguments on the “proper” test and render the individual mandate unconstitutional.

Jack Painter is the founder of Liberty Alliance Cincinnati and is on the board of the Ohio Liberty Council.