Cuccinelli testified before a House Judiciary Committee Wednesday.
Cuccinelli said the law's individual mandate, which would force people to pay a penalty for not buying insurance, represents a limitless expansion of federal powers.
"Until the United States can articulate a constitutional boundary to the power that it proposes the federal government has, it should lose in the Supreme Court," Cuccinelli says.
Making the case for the health care law was Walter Dellinger, a former U.S. solicitor general.
"Congress, of course, has no free-standing power to regulate inactivity -- it has a variety of powers it can sometimes use to impose affirmative obligations," Dellinger says. "That's what we're talking about."
Lawmakers agreed that the debate will ultimately be decided in the courts.