Byron York
It's always been a challenge for Mitt Romney to explain the differences between Romneycare and Obamacare. The two programs share a lot of the same features -- mandate, penalties, subsidies, exchanges and others. Romney has consistently argued that those provisions are acceptable, even good, at the state level, but not acceptable, and in some cases not even constitutional, at the federal level.

The problem isn't just that Romney frequently finds himself making detailed explanations, which is never a good thing in politics. The problem is that it always sounds a little odd to voters for Romney to say that when he did it in Massachusetts, it was a great thing, but when Barack Obama did it nationwide, it was a terrible thing.

Now, in the wake of the Supreme Court's Obamacare decision, Romney's job has gotten even harder -- so hard that there will likely be growing pressure on him to admit that Romneycare, his signature achievement as Massachusetts governor, was a mistake.

The problem is the court's ruling that Obamacare's individual mandate is a tax. Even though most Republicans had wanted to see Obamacare struck down, many embraced the mandate-is-a-tax ruling because it allowed them to accuse the president of raising taxes.

Romney, however, did not jump on the bandwagon, and the reason was Romneycare. If Romney denounced Obama's mandate as a tax, then what about the mandate he imposed in Massachusetts?

On July 2, top Romney adviser Eric Fehrnstrom told MSNBC that Romney did not believe the mandate is a tax, that it is instead a penalty. That wasn't a gaffe; Fehrnstrom was accurately stating Romney's position. But his words created controversy after Democrats and the press pointed out the gulf between Romney and other Republicans.

So on July 4, Romney himself came forward to clear things up. "The Supreme Court has the final word, and their final word is that Obamacare is a tax," he told CBS News' Jan Crawford. "So it's a tax."

When Crawford asked whether that meant Romneycare's mandate was also a tax -- and thus whether the former governor had raised taxes in Massachusetts -- Romney said no. The court made a distinction between a mandate imposed by a state and one imposed by the federal government, he explained: Obama's is a tax, and mine isn't.

The court didn't actually say it quite so clearly, but there's no doubt Romney and the Massachusetts legislature had the authority to impose an individual mandate in the state. The bottom line for this election, however, is that Romney is making another fine, legalistic distinction so he can keep vowing to repeal Obamacare while at the same time defending Romneycare.

Byron York

Byron York, chief political correspondent for The Washington Examiner