The manner in which Obamacare was written has some peculiarities that make it peculiarly flexible in the following sense of the Pelican Brief.
They chose to rationalize the law, and so argued before the Court, and this after being offered an out, on the grounds of the Commerce Clause, even though they would have been on far stronger ground to argue that this clause justified what they wanted to do from Article One, Section Eight:
The Congress shall have Power To lay and collect Taxes, Duties, Imposts and Excises, to pay the Debts and provide for the common Defence and general Welfare of the United States...To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers...
Since the Obama folks didn't make that argument, they defaulted to what the Court will chose as to the amicus briefs, which they can, but are not required, to use.
Given the intensity of debate over Obamacare, there will exist a Pelican Brief that argues that in fact, Obamacare is in really a tax measure as to the treatment of healthcare insurance, including the individual mandate, if for political reasons, it was thought expedient not to advertise that fact.
You don't pay taxes on health insurance benefits, although the professional opinion of healthcare economists is that it overincentivizes the consumption of healthcare at the expense of other goods, especially low deductible policies with no co-pays.
If the Court had asked the question, "Can the State tax cigarettes more than broccoli?" it would have been closer to the mark, although whether Obamacare in practice would serve the General Welfare would depend to some views as to cost, especially medical malpractice, but also other incentives in that industry, and whether a sweeping change in one seventh of the economy could ever be done without generating uncertainty that became more of a cost than a benefit in and of itself, although once things go forward, that would change too.
Of course, the reason that it was thought inexpedient to make that taxation argument is that then people could scream that Obama had raised taxes, something politicians are loathe to do. If the Court so choses, it doesn't have to use the amicus brief that does exist, Obamacare as Pelican Brief, but it could.
As to the second part of Obamacare that is unusual, it has a potential auto-destruct mechanism built into it that had to have been understood, since its alternative is so routine; the question of severability.
The vast majority of laws have written in it a severability clause that states something to the effect of "Whatever clauses not found unconstitutional are to be treated as law."
Arizona's immigration law went forward for precisely that reason, and since there are plenty of lawyers in the Obama Administration, that was a choice that had to have been understood.
Of course, they also know that there would exist a Pelican Brief that argues that there is a large amount of administrative discretion in a tax code measure as determined by the IRS rulings, and Congressional revision, like the Supreme Court case that made healthcare a tax code issue in the first place by saying that dollars provided to buy health insurance aren't taxed as income, a policy decision of vast consequences as to the world we live in today.