“If I wanted to sponsor a bill,” Sen. Tom Coburn (R-OK) asked, “and it said, ‘Americans, you have to eat three vegetables and three fruits every day,' and I got it through Congress and it’s now the law of the land... does that violate the Commerce Clause?” Elena Kagan looked puzzled. “Sounds like a dumb law,” she said.

When Kagan failed to say clearly that Congress didn’t have the power to “tell people what they have to eat every day,” Republicans circulated the video of from her confirmation hearings as evidence that she “views the power of government to be essentially without limit.”

Part of the problem was the way the question was worded. Coburn’s hypothetical three-square-meal law would not technically “violate” the Commerce Clause of the Constitution, which says nothing whatsoever about what Congress can’t do. Coburn presumably meant to ask whether the Commerce Clause, which gives Congress the power “to regulate commerce... among the several States,” would grant Congress the power to pass such a law. And, as Kagan ultimately pointed out, while the courts have traditionally allowed Congress to interpret the Commerce Clause quite broadly, it does not give Congress the power to regulate non-economic activities like eating.

For many conservatives, the broad power to regulate commerce—which is well-established in the courts—is behind the expansion of government into all sorts of things that are none of its business. Congress may not be able to require us all to eat our veggies, but it probably can use the Commerce Clause to regulate the amount of sodium or transfats in foods, just as it can regulate the sale of cigarettes. Key provisions of the health care reform bill—which Coburn admitted was the veiled target of his question—rely upon the Commerce Clause. Of course, conservatives generally object less to using the Commerce Clause to prohibit the sale of marijuana, even where it doesn't cross state lines. And the truth is that it would be difficult for the country to function in the modern world without some national regulatory power.

The idea that jackbooted liberal thugs might take away Coburn’s Hot Pockets may seem silly, but the underlying issue is a serious one. To what extent should the government force us to do what it thinks is good for us? The government requires to wear seat belts on the paternalist grounds that although we may find it annoying it saves many thousands of our lives. We likewise fluoridate the water on the grounds that it is tremendously effective in preventing tooth decay and gum disease. By forcing people to take better care of themselves, these policies also reduce the public cost of responding to injury-accidents or treating mouth disease. These policies nevertheless passed only because most of us don’t find either of them particularly burdensome, although adding fluoride to the water did prompt fears of a communist plot to poison or drug us.

Jacob Appel's suggestion—featured in Big Think’s Dangerous Ideas series—that we also add lithium to the water is unlikely to go anywhere. It may be that putting trace amounts of lithium, which is still widely used as an anti-depressant, in the water would save thousands of lives by preventing suicides. But even in "non-therapeutic" doses lithium would work only by affecting our brain chemistry in ways that are still poorly understood. While the fact that higher levels of lithium are naturally present in some water shows that it is not especially harmful at those doses, deliberately doping the general population with trace amounts of a mood-altering medication without their permission—and without knowing exactly how it will affect them all—surely would violate their rights. And if lithium affects attitudes enough to keep them from killing themselves, it seems likely that it could also affect their attitudes toward the government, which would raise the question of whether the government is using drugs to keep people from dissenting.

But as more people die from heart attacks and diabetes and other diet-related diseases—and the costs associated with managing and treating these diseases skyrockets—legislatures will consider new regulations on what goes into the food we eat. The fact is that whole industries are set up to convince people to consume or do things that are not particularly good for them. Coburn’s fears of being forced to eat his veggies may be misplaced, but new regulations would affect what foods are available and how much they cost. And the question of what the state can do to help us make better private decisions without limiting our freedom will increasingly be at the heart the debate between liberals and conservatives over what kind of government we should have.