…$1 billion tax on nonpossession of Chevy Volts. Not a mandate!
UPDATE: Roberts’ opinion actually addresses my concern:
First, for most Americans the amount due will be far less than the price of insurance, and, by statute, it can never be more. It may often be a reasonable financial decision to make the payment rather than purchase insurance, unlike the “prohibitory” financial punishment in Drexel Furniture. 259 U. S., at 37. Second, the individual mandate contains no scienter requirement. Third, the payment is collected solely by the IRS through the normal means of taxation—except that the Service is not allowed to use those means most suggestive of a punitive sanction, such as criminal prosecution. See §5000A(g)(2). The reasons the Court in Drexel Furniture held that what was called a “tax” there was a penalty support the conclusion that what is called a “penalty” heremay be viewed as a tax. . . .
The bottom line is that a sufficiently ineffective mandate can count as a tax. Mull that one over.
PILEUS 
$1.50 tax per meal if you don’t eat your broccoli. Not a mandate!
$49.99 a month if you don’t join a gym. Not a mandate!
Of course, when these laws are written, the pols will insist it is not a tax but a mandate. Court has secret decoder ring that converts that language on the way over to them.
I wonder whether there are any limits, though. Could you impose an essentially infinite tax in order to force everyone to comply or go to prison? Are there any such limits to Roberts’ logic? After all, we could just punish crimes the same way: impose a super-high tax on it that no one could pay, then send violators to prison for tax evasion. Mandate, tax – a distinction without a difference, it seems to me.
Guess Roberts wasn’t part of the law and economics revolution!
Huge victory for courts and lawyers who could have a lot of future work in which they are asked to decide which taxes/mandates are too excessive and which are trivial?
Looks that way to me. Of course, this case could end up being sui generis. Given the controversy, Congress may decide to hold off on the mandating for a few years.
And then will use this precedent for the next step up the rachet (and decline on Hayek’s road).