The attorneys general of at least eleven states will file lawsuits over the constitutionality of the individual mandate in the health-care act, which is scheduled to be signed into law tomorrow:

“The health care reform legislation passed by the U.S. House of Representatives last night clearly violates the U.S. Constitution and infringes on each state’s sovereignty,” Florida Attorney General Bill McCollum, a Republican, said in a prepared statement announcing a news conference.
“On behalf of the State of Florida and of the Attorneys General from South Carolina, Nebraska, Texas, Utah, Pennsylvania, Washington, North Dakota, South Dakota and Alabama if the President signs this bill into law, we will file a lawsuit to protect the rights and the interests of American citizens.”

Virginia will also join in the fight:

Attorney General Kenneth Cuccinelli, a Republican, said on Monday that Congress lacks authority under its constitutional power to regulate interstate commerce to force people to buy insurance. He said the bill also conflicts with a state law that says Virginians cannot be required to buy insurance. “If a person decides not to buy health insurance, that person by definition is not engaging in commerce,” Cuccinelli said in recorded comments. “If you are not engaging in commerce, how can the federal government regulate you?”

UPDATE: A statement from Washington attorney general Rob McKenna, who today announced he will join the suit:

“I’m concerned that the measure unconstitutionally requires all Washingtonians to purchase health insurance and places an extraordinary burden on our state budget by requiring Washington to expand its Medicaid eligibility standards in violation of our state’s rights guaranteed under the 10th amendment.”
“I believe this new federal health care measure unconstitutionally imposes new requirements on our state and on its citizens. This unprecedented federal mandate, requiring all Washingtonians to purchase health insurance, violates the Commerce Clause and the 10th amendment of the US Constitution.”

UPDATE II: Ed Morrissey points to a 1994 CBO memorandum calling an individual mandate to provide insurance coverage “unprecedented.”

A mandate requiring all individuals to purchase health insurance would be an unprecedented form of federal action. The government has never required people to buy any good or service as a condition of lawful residence in the United States. An individual mandate would have two features that, in combination, would make it unique. First, it would impose a duty on individuals as members of society. Second, it would require people to purchase a specific service that would be heavily regulated by the federal government.
Federal mandates typically apply to people as parties to economic transactions, rather than as members of society. For example, the section of the Americans with Disabilities Act that requires restaurants to make their facilities accessible to persons with disabilities applies to people who own restaurants. The Federal Labor Standards Act prohibits employers from paying less than the federal minimum wage. This prohibition pertains to individuals who employ others. Federal environmental statutes and regulations that require firms to meet pollution control standards and use specific technologies apply to companies that engage in specific lines of business or use particular production processes. Federal mandates that apply to individuals as members of society are extremely rare. One example is the requirement that draft-age men register with the Selective Service System. The Congressional Budget Office (CBO) is not aware of any others imposed by current federal law.