Ilya Shapiro points out an interesting exchange from the oral argument on ObamaCare.  When the Solicitor General asserted that the Court “has got an obligation to construe [the mandate] as an exercise of the tax power, if it can be upheld on that basis,” the Chief Justice interrupted him, and they had the following exchange:

CHIEF JUSTICE ROBERTS: Why didn’t Congress call it a tax, then?

GENERAL VERRILLI: Well—

CHIEF JUSTICE ROBERTS: You’re telling me they thought of it as a tax, they defended it on the tax power. Why didn’t they say it was a tax?

GENERAL VERRILLI: They might have thought, Your Honor, that calling it a penalty as they did would make it more effective in accomplishing its objective. But it is—in the Internal Revenue Code it is collected by the IRS on April 15th. I don’t think this is a situation in which you can say—

CHIEF JUSTICE ROBERTS: Well, that’s the reason. They thought it might be more effective if they called it a penalty.

GENERAL VERRILLI: Well, I—you know, I don’t—there is nothing that I know of that illuminates that, but certainly…

What caused Roberts to adopt the position put forth by the bumbling Verilli?  Speculation continues, but as Ilya suggests, perhaps Roberts was against treating the mandate as a tax before he was for it.