Barack Obama suffers latest blow as part of health care law deemed unconstitutional

Judge Henry Hudson refused to freeze the law, but his ruling will cast a shadow over a reform that Mr Obama spent 18 months battling for and expended immense amounts of political capital on. The ruling all but guarantees that legal arguments will proceed all the way to the Supreme Court.

The judge, a Republican appointed by previous President George W Bush, supported the argument that the law's requirement Americans must buy health insurance or face a fine exceeded the federal government's power under the constitution. Health care insurance is currently optional.

The Justice Department has argued that the mandate is a proper exercise of the government's authority.

The case was brought by Ken Cucinelli, the Attorney General of Virginia, in defence of a law passed in his state banning the requirement.

White House officials had expected to lose the ruling, but professed to be nonplussed because the mandate does not come into force until 2014.

Barack Obama suffers latest blow as part of health care law deemed unconstitutional