Gov. Haley Barbour says Mississippi has joined a multi-state lawsuit challenging the federal health care overhaul.
Barbour has been saying for weeks that he intended to join the suit. He made it official Friday.
Barbour, a Republican, calls the federal law an "unprecedented expansion of federal power."
He says the Constitution does not give Congress the power to require people to buy health insurance.
Mississippi is one of 20 states involved in the lawsuit, which is led by Florida.