Is it an excise? No.
Is it a duty? No.
Is it an impost? No.
Is it apportioned among the several States? No.
Is it a tax on income? No.
Therefore, it is not a tax in the forms that the Constitution grants taxing power to Congress.
Republicans who are jumping on the "tax increase" bandwagon are idiots.
The Supreme Court, which has the final say, says it is a tax.
I'm having trouble fathoming this comment.
The phrase "tax increase" is toxic in a presidential campaign.
Regardless of whether its a fine, or a tax, or a mandate, shouldn't Romney shove the SCOTUS ruling down Obama's throat by using the phrase, now that they've salvaged his signature legislation by using the "tax increase" rationale?
And therein lies the poison pill; Roberts only ruled that the mandate represents a tax. He did not rule on what kind of tax it might be, nor on the constitutionality of the specific tax itself.
The challenge will now be focused on the tax. Since the kind/type of tax isn't specified in the original act, it may be as simple as a lower court simply declaring the tax as unconstitutional, because it doesn't meet any the criteria you listed.
If a court allows Congress to refine/define what kind/type of tax it is, and if Congress doesn't then act, it could also die. Or, it could rule that the tax falls within one of your criteria, but then that opens up a whole new set of challenges regarding exemptions, etc.
Roberts is either a genius for throwing this in the quagmire of tax details, or he lit the fuse for CWII. If we start to see the next series of legal challenges, I will stick with my opinion #1.