Tomorrow, the United States Supreme Court continues hearing arguments regarding the Patient Protection and Affordable Care Act (PPACA), a.k.a., Obamacare. This time, the Court will consider the arguments related to the "main event" of the hearings: the constitutionality of the law's individual mandate. The individual mandate requires every American, with a few exceptions, to purchase a government-approved health insurance plan, or be forced to pay a fine.

Modern jurisprudence has increasingly allowed the federal government to regulate commerce that is not of an obviously interstate nature. The issue here is that PPACA goes further and regulates the non-purchase of a good or service. Rather than simply regulating the manner in which the health insurance market will operate, PPACA requires that everyone in the country buy something, or be fined. Under this paradigm, market participation would no longer be required for regulation under the Commerce Clause; instead, and in a very real way, the feds would subject you to a purchase requirement merely for being a living, breathing American.

That is a problem. Having a health insurance plan makes sense, but compelling Americans to buy a health insurance plan through heavy-handed federal coercion is awful policy and arguably unconstitutional. Reading into the U.S. Constitution a federal right to demand purchases from its citizens would eviscerate many of the limits on government power enshrined in that document.

If the federal government can require individuals to purchase health insurance, what can't the federal government require us to purchase? Ilya Somin, a law professor at George Mason University who has filed a brief with the court, contends that if PPACA passes constitutional muster, then Congress could pass "a broccoli mandate, a car-purchase mandate, really any other mandate that you'd want." Where is the line against such coercion drawn if not by the plain meaning of the Constitution?

Proponents of PPACA have dismissed the suggestion that the federal government would impose a "broccoli mandate," arguing that the federal government would never try to expand a mandate to purchase goods and services into such areas. But Americans should not have to entrust their freedoms to the word of politicians and bureaucrats, well-meaning or not.

There is no "just trust us" clause in the Constitution. The Constitution is the check that keeps capricious leaders from doing capricious things, and should remain so.