But whatever you want to call it -- tax, fee, penalty, incentive, Robert -- even though it does raise some money, the key is that it will snag relatively few people. Citing CBO, the Court noted "it is estimated that four million people each year will choose to pay the IRS rather than buy insurance. ... It suggests instead that the shared responsibility payment merely imposes a tax citizens may lawfully choose to pay in lieu of buying health insurance."
Four million. A bit more than one percent of the population. And remember, these are people who are able to afford insurance but choose not to, knowing they'll eventually need to avail themselves of the health care system. It's actually fair to think of it as a free-rider penalty. That's harder to explain than simply screaming "tax," but it's true, and much less politically contentious.