"It's a hard case," said Lackland Bloom Jr., a professor and constitutional law specialist at Southern Methodist University Dedman School of Law.
Since the New Deal, the Supreme Court has generally given Congress broad power to regulate interstate commerce, said Bloom, the SMU law professor.
An exception came in 1995, when the court struck down a law that made it a federal crime to bring a gun into a school zone.
Congress justified the law under the Commerce Clause, saying costs associated with gun violence eventually affected the national insurance market, but the court disagreed, Bloom
The court used similar reasoning in 2000 in striking down a provision of the Violence Against Women Act that made sexual assault a federal civil offense, he
The ruling was partly based on the idea that if the government has a pervasive regulatory program, such as the Controlled Substances Act, it can regulate beyond the scope of the Commerce Clause to protect that program, Bloom
Many legal scholars, including Bloom
, say even if the mandate is struck down, the court is unlikely to invalidate the entire health care law.