WINSTON-SALEM - Much of the focus of the debate over President Obama's signature health care law was on the individual mandate provision.

A Wake Forest University professor who spearheaded a legal brief on behalf of the Affordable Care Act said the court's ruling to uphold the individual mandate section under Congress' power to tax came as a surprise.

"Chief Justice Roberts walked a fine line and on this question he sort of split the baby, if you will, as King Solomon did in the Bible by saying on the one hand it's not a regulation but on the other hand we give every benefit of the doubt to Congress, particularly in areas of social and economic legislation," said Mark Hall, a professor of law and public health.

The mandate requires nearly all U.S. citizens and legal residents to buy health coverage by 2014. Hall says the mandate is the linchpin of the Affordable Care Act, which requires insurance companies to accept everyone.

"It doesn't work unless you require everybody who can afford it to get coverage because if you just let people sit on the sidelines and buy insurance on the way to the hospital then the market would collapse, basically," Hall said.

Hall said the individual mandate does not apply if insurance would cost a person more than 8 percent of his/her income, so, an estimated 20 million Americans would continue to receive care in places including emergency departments and free clinics.

"Right now we have 50 million people uninsured and so reducing that to 20 million is a major accomplishment," he said.

Hall was the first to author an extended analysis of the constitutionality of the individual mandate, which was used by the U.S. Senate to help support the case for enacting it.

He said the court's ruling on the Affordable Care Act was a defining moment in health care and health care law.

"There's never been a case more important than this,” he said. “It's hard to imagine that there will again be a case of this magnitude for defining what our health care system is and how it functions."