How any conservative could vote for Romney (and polls show there are plenty of them) is beyond my realm of comprehension.

(CNS News) — Republican presidential hopeful Mitt Romney’s biggest challenge in the GOP primary might be explaining the differences between Romneycare and Obamacare — how the health care plan he signed as governor of Massachusetts in 2006 differs from the federal health care reform enacted last year.

Beyond differences the two plans may have, the linchpin of both is considered the individual mandate: the requirement that individuals buy health insurance or pay a penalty. Twenty-seven states have sued to have this mandate in Obamacare ruled unconstitutional, and two federal courts have declared it unconstitutional.

But Romney, as recently as 13 months ago, has staunchly defended the mandate in the law that he signed in 2006, arguing that it forces people to take responsibility for their own health care.

“Let me tell you, there’s a big difference between what we did and what President Obama is doing,” Romney said in a Mar. 7, 2010 Fox News Sunday interview.

“What we did, I think, is the ultimate conservative plan. We said people have to take responsibility for getting insurance, if they can afford it, or paying their own way. No more free-riders. And we solved this at the state level — not a federal plan, but a state plan.”

Romney went on to describe the mandate as the “biggest pro” of his health care plan.

“It’s a plan that has pros and cons,” he said. “The biggest pro, in my view, is that we don’t have free riders now expecting other people to pay for their health care costs. And we’re also able to have individuals, who otherwise would not have the kind of specialty care they need, receiving treatment.”