A judge in Virginia also rejected the mandate, but two judges in other states have upheld it.

In his ruling, Vinson went further than the Virginia judge and declared the entire health care law unconstitutional, The Associated Press reported Monday.

"This is obviously a very difficult task. Regardless of how laudable its attempts may have been to accomplish these goals in passing the act, Congress must operate within the bounds established by the Constitution," Vinson wrote in his 78-page ruling.

At issue is whether the government is reaching beyond its constitutional power to regulate interstate commerce by requiring citizens to purchase health insurance or face tax penalties.

Attorneys for President Barack Obama's administration argued the health care system was part of the interstate commerce system. They said the government can levy a tax penalty on Americans who decide not to purchase health insurance because all Americans are consumers of medical care.

But attorneys for the states said the administration was essentially coercing the states into participating in the overhaul by holding billions of Medicaid dollars hostage. The states also said the federal government is violating the Constitution by forcing a mandate on the states without providing money to pay for it.

Florida's former Republican Attorney General Bill McCollum filed the lawsuit just minutes after Obama signed the 10-year, $938 billion health care bill into law in March. He chose a court in Pensacola, one of Florida's most conservative cities. The nation's most influential small business lobby, the National Federation of Independent Business, also joined.

Other states that joined the suit are Alabama, Arizona, Colorado, Georgia, Indiana, Idaho, Iowa, Kansas, Louisiana, Maine, Michigan, Mississippi, Nebraska, Nevada, North Dakota, Ohio, Pennsylvania, South Carolina, South Dakota, Texas, Utah, Washington, Wisconsin and Wyoming.

The Associated Press contributed to this report.