The individual insurance mandate in President Barack Obama’s health care overhaul was ruled unconstitutional by a divided U.S. appeals court in Atlanta today.

The court sided with 26 states who challenged the law on the grounds that Congress exceeds its constitutional power in forcing individuals to purchase health insurance or face a penalty.

The U.S. Court of Appeals for the 11th Circuit struck down the insurance mandate in a two-to-one decision that represents the biggest defeat to the law to date, the Wall Street Journal reported.

"This economic mandate represents a wholly novel and potentially unbounded assertion of congressional authority: the ability to compel Americans to purchase an expensive health insurance product they have elected not to buy, and to make them re-purchase that insurance product every month for their entire lives," Judges Joel Dubina and Frank Hull said in a jointly written opinion.

The decision falls in line with a January ruling by U.S. District Judge Roger Vinson of Florida, but overturns a Cincinnati-based 6th Circuit Court of Appeals ruling in June that upheld the law.

Challengers to the law took their complaints to the Supreme Court for the first time late last month, lead by the Thomas More Law Center, a Michigan-based firm generally focused on promoting religious freedom for Christians.