Thoughts on "The Broccoli Objection"

Over at Balkinization, Andrew Koppelman discusses what he calls "the Broccoli Objection" to the constitutionality of the individual mandate aspect of Obamacare.  The Broccoli Objections was first made by U.S. District Court Judge Roger Vinson, during the oral argument preceding his decision to strike down the individual mandate:

In the broadest sense every decision we make is economic. The decision to marry. The decision to keep a job or not has an economic effect. If [the federal government] decided everybody needs to eat broccoli because broccoli makes us healthy, they could mandate that everybody has to eat broccoli each week?

Koppelman thinks this objection "rests on a simple mistake: treating a slippery slope argument as a logical one, when in fact it is an empirical one."  He quotes Frederick Schauer for the proposition that "any slippery slope argument depends on a prediction that the instant case will in fact increase the likelihood of the danger case," and dismisses the Broccoli Objection because "Congress is never going to force you to eat your broccoli."  Q.E.D.

I think Koppelman misunderstands the logical structure of the Broccoli Objection.  It really is not a slippery slope argument -- it is a reductio ad absurdum.  Here is the structure of the objection, as I see it:


Premises
1)  The constitution imposes significant limits on the power of Congress;
2)  If the individual mandate is within Congress's power under the Commerce Clause, then, by the same principle, so would be the Broccoli mandate;   
3)  If the Broccoli mandate is constitutional, then there are no significant limits on Congress's power.


If all three premises are true, absurdity results because it would be both true and false that there are limits on Congress's power.  So not all three premises can be true.


So is the Broccoli Objection effective?  Not in my opinion.  I think premise 2, and probably premise 3, are actually false.  For example, you can craft a principle by which the individual mandate is within Congress's power (as necessary and proper to an otherwise clearly constitutional attempt to regulate the market for health insurance) and the Broccoli Mandate is not (because it is not necessary and proper to any otherwise constitutional exercise of Congressional power).   

But the objection is best defeated on its own terms -- not by transforming it into a more-easily dismissed slippery slope argument.