No it's not, just ask the Etch A Sketch Boy

"The governor [Romney] believes what we put in place in Massachusetts was a penalty and he disagrees with the Court’s ruling that the mandate was a tax."

The original author of the mandate ought to know. And, as for John Roberts, who gives a fuck what he calls it? He's criminal lawyer - certainly not a constitutional lawyer - see Citizens United - and not an accountant, economist or even a tax lawyer so little fascist boy can call it anything he wants. And Romney agrees with me.