A federal judge declared the Obama administration's health care overhaul unconstitutional Monday, siding with 26 states that argued people cannot be required to buy health insurance.

Senior U.S. District Judge Roger Vinson agreed with the states that the new law violates people's rights by forcing them to buy health insurance by 2014 or face penalties. He went a step further than a previous ruling against the law, declaring the entire thing unconstitutional if the insurance requirement does not hold up.

Attorneys for the administration had argued that the states did not have standing to challenge the law and that the case should be dismissed.

Justice Department spokeswoman Tracy Schmaler said Monday the department strongly disagrees with Vinson's ruling and intends to appeal.

"There is clear and well-established legal precedent that Congress acted within its constitutional authority in passing this law and we are confident that we will ultimately prevail on appeal," she said in a statement.

The final step will almost certainly be the U.S. Supreme Court. Two other federal judges have already upheld the law and a federal judge in Virginia ruled the insurance mandate unconstitutional but stopped short of voiding the entire thing.

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