Attorneys-general from 13 states, led by Florida, on Tuesday filed a lawsuit challenging an overhaul of America's $2.5 trillion health-care system minutes after US president Barack Obama signed the landmark reform legislation.
The lawsuit by a dozen Republicans and one Democrat claims that the sweeping reforms violate state government rights in the US constitution.
It was filed electronically with a federal court in Pensacola, Florida, according to the office of Florida attorney-general Bill McCollum.
The White House has said the suit will fail.
The lawsuit says the law — which expands the government health plan for the poor, imposes new taxes on the wealthy, and requires insurers to cover people with pre-existing medical conditions — violates the constitution's commerce clause by requiring nearly all Americans to buy health insurance.
"This lawsuit should put the federal government on notice that Florida will not permit the constitutional rights of our citizens and the sovereignty of our state to be ignored or disregarded," McCollum said in a news release.
State officials also said the bill signed by Obama shortly before midday on the east coast was at odds with the US constitution's tenth amendment, which says, "Powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states."
In addition to McCollum, the Republican attorneys-general from South Carolina, Nebraska, Texas, Utah, Alabama, Colorado, Michigan, Pennsylvania, Washington, Idaho, and South Dakota joined the suit, according to the Florida news release.
James Caldwell, Louisiana's Democratic attorney-general, is also a plaintiff. Virginia's Republican attorney-general was expected to file a separate lawsuit against the law passed by the Democrat-dominated Congress.