Coburn, a medical doctor, praised the Obama administration for tackling the nation's healthcare probelms, but said the reform law is unaffordable and
"I praise the Obama administration for wanting to address the issue. There's no question we have a problem, healthcare costs too much, but every claim about this bill is going to be disproven," said Coburn on CBS's "This Morning" Tuesday.
The Justice Department claims that the mandate to purchase health insurance is a valid use of Congress’s power to regulate commerce.
The decision to remain uninsured affects economic activity, the government argues, because billions of dollars in unpaid medical bills are shifted to taxpayers and people with insurance.
Opponents say the mandate is unconstitutional because it requires people to purchase a product. Congress can regulate economic activity but cannot “compel” people to engage in it, they argue.
Coburn said he believes the expansion of the Commerce Clause is the reason the United States is "running trillion dollar deficits."
"We're in such a big financial hole. If you go back to look at why we are is because the federal government has gotten outside the bounds of what we were ever intended to do and one of the ways we did that is by expanding the Commerce Clause to have us involved in things that are really not our purview under the Constitution," he said.
The Oklahoma senator called for healthcare reform that allows people to buy insurance in an open marketplace across state lines.
"Before we criticize the market base, we ought to go back and say we could we have a real market and we haven't done that," he added.
—Sam Baker contributed to this story.