A U.S. federal appeals court has upheld President Barack Obama's health care reform law, which has faced a series of legal challenges since it passed last year.

The court in Ohio ruled 2 to 1 Wednesday THAT a provision in the law mandating that Americans buy health insurance by 2014 or pay a penalty is not unconstitutional.

Writing for the majority, a judge determined that Congress has a rational basis for concluding the minimum coverage provision is key to the law's larger reforms in health care delivery and insurance.

Opponents of the provision had argued it exceeds Congress' regulatory powers by requiring Americans to buy health insurance or pay a fine.

The U.S. Justice Department welcomed the ruling and vowed to “vigorously defend” Mr. Obama's health care law.

The Ohio case was one of three major challenges to the law that are expected to go to the U.S. Supreme Court. Federal appeals courts in Virginia and Georgia are also hearing challenges to the measure.

In all, there are about 20 lawsuits against the health care reform law, which seeks to extend health care coverage to millions of Americans who lack it.