In an unexpected about-face on Wednesday, Republican presidential candidate Mitt Romney called the individual mandate fee under President Barack Obama's health care plan a tax, rather than a penalty.

The Patient Protection and Affordable Care Act -- also known as Obamacare -- was last week upheld, almost in its entirety, by the U.S. Supreme Court. Five of the nine justices approved the act's highly controversial individual mandate, which requires citizens to pay for health insurance if they can afford it. Starting in 2014, those who decline to purchase a health care plan will pay a fee to the Internal Revenue Service.

Chief Justice John Roberts' controlling opinion said the fee was constitutional only as a tax -- not, as both Obama and Romney both defined it in a rare synchronicity, as a penalty under the Constitution's Commerce Clause.

The majority of the court said it's a tax and therefore it is a tax. They have spoken, said Romney to CBS News on Wednesday. There's no way around that. You can try and say you wish they had decided a different way but they didn't. They concluded it was a tax.

This is a blatant contradiction to Romney's previous position. Just two days ago, in fact, Republican campaign spokesman Eric Fehrnstrom affirmed that long-held position. But from Independence Day onward, that's apparently out the window.

The Obamacare individual mandate has become the center of a political firestorm -- Republicans object to what they see as a forced purchase and a blow to states' rights, while Democrats argue that enforcing the mandate is the only way to make insurance available to everyone.

Romney is caught in the middle, since he implemented a successful health care plan that included an individual mandate when he was the governor of Massachusetts in 2006, but was forced to disavow its key principles in order to please the Republican base. He's been called a flip-flopper on many issues, and Wednesday's comments aren't likely to help matters.