One of the problems I have with the current challenges to the health insurance reform, and in particular the mandate, is that I am, to a large degree, convinced by the arguments of the challengers. I'm no lawyers by any stretch of the imagination, but I cannot find any precedent for the federal government to compel people to buy something from a private provider solely because these people have not chosen to buy such a product. I am also concerned by some of the reductio ad absurdum arguments that even if the "penalty" is a tax that can be rebated upon purchase of insurance, one still cannot "sortir de l'embrras." As Jason Kuzinicki points out, such logic might one day be conceivably used to justify corvee style labor (although one would hope the 13th amendment might prevent such an imposition).
There are counterarguments to these opponents, and I don't find them wholly non-compelling (neither without all the negatives I mightn't use in this sentence): namely, mandating such a purchase is a "proper" exercise of Congress's power to regulate interstate insurance markets, the latter power even most opponents of the reform do not seem to seriously contest. This counterargument makes enough sense to me that I won't concede the unconstitutionality of the mandate, but I must say that I am more convinced by the opponents' claims.
But what I am more convinced of is that the mandate requirement is so inextricably bound with the bulk of the health insurance reform that if it is unconstitutional, the rest of the bill (or most of it, in particular the pricing provisions and bans against lifetime caps and restrictions based on pre-existing conditions) ought to be as well. In other words, Judge Vinson's opinion, which I have actually read (okay, I "skimmed" it), makes more sense to me than Judge Hudson's opinion, which I haven't read but have read summaries of. Both judges find the mandate unconstitutional, but Mr. Vinson would strike down the entire law and Mr. Hudson would strike down only the mandate.
The problem with all this is that I support the health insurance reform and even the mandate, although I would welcome changes that would do away with the mandate in exchange for another policy (an open-enrollment window with higher premiums for those who fail to enroll during that period seems the most doable politically, but something like a public option, or as I have argued for elsewhere, an interim public option, might work, but maybe not, as I'm no expert). I have a hard time, however, justifying its constitutionality even to myself. I do not follow any particular mode of constitutional interpretation--some amalgam of originalism, textualism, and "living constitution" and the kitchen sink appeals to me and makes more sense than strict adherence to one or the other--but I cannot come up ex nihilo with some theory to justify a mandate and defend it to justify Mr. Kuzinicki's specter of corvee labor.
More than my desire for intellectual consistency and overcoming my own [warning!!!! I'm about to use a buzz word] cognitive dissonance, I should say I am a partisan in favor of the bill. I have taken my position and even very early on acknowledged these constitutional difficulties (and others too, see here, here, and here.)
My only real rationalization--I cannot call it a justification--rests on a factual claim not (yet) in evidence, namely, that the mandate and the broader health insurance reform will achieve its goal of making decent health care affordable to almost everyone: the rationalization is that the mandate, for all its constitutional difficulties and for all the dangers that pushing the limits of the constitution imply, does not scare me. If the federal government really embarks on a corvee labor scheme (as opposed to, say, merely trying to draft striking railway workers into the military as Mr. Truman threatened to do when he was president), we have bigger problems than whether the district courts will uphold such a measure. (As an adhominemish aside, I might imagine some of the very opponents of the health insurance mandate writing in the case of a Truman style draft law that "in order to preserve the dignity of labor and railway workers' liberty of contract, we need to approve drafting the entire nation's labor force to guarantee their right to a steady job." But I should be chary of criticizing anyone for a hypothetical in order to deflect my very real-life support of a policy.)
As another, related rationalization, other nations have some version of a mandate, and the walls haven't come tumbling down. But to paraphrase Christopher Marlowe, "that was in another country, and besides, the insurers are all non-profits."