CHICAGO (Reuters) - Republican attorneys general in at least 12 states warned on Monday that lawsuits will be filed to stop the federal government’s healthcare reform bill from encroaching on states’ sovereignty.

The lawsuits were widely expected with announcements coming from the states’ top legal officials less than 24 hours after the House of Representatives gave final approval to a sweeping overhaul of healthcare.

State officials are concerned the burden of providing healthcare will fall to them without enough federal support.

Eleven of the attorneys general plan to band together in a collective lawsuit on behalf of Alabama, Florida, Michigan, Nebraska, North Dakota, Pennsylvania, South Carolina, South Dakota, Texas, Utah and Washington.

“Congress’ attempt to force Michigan families to buy health insurance -- or else -- raises serious constitutional concerns,” said Michigan Attorney General Mike Cox. “We will fight to defend the individual rights and freedoms of Michigan citizens against this radical overreach by the federal government.”

The state attorneys general say the reforms infringe on state powers under the Constitution’s Bill of Rights.

Virginia Attorney General Kenneth Cuccinelli, who plans to file a lawsuit in federal court in Richmond, Virginia, said Congress lacks authority under its constitutional power to regulate interstate commerce to force people to buy insurance. The bill also conflicts with a state law that says Virginians cannot be required to buy insurance, he added.

“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?”

Forrest McDonald, a retired University of Alabama history professor who has written a book on states’ rights, said Congress has no power to make someone buy something.

“You can stretch it all to hell and you’re going to find a lot of power, but you can’t find the power to make me buy a car or anything,” he said.

But Mark Rosen, a Constitution scholar at Chicago-Kent College of Law, said the states do not really have a constitutional leg to stand on.

“Congress has clear authority to pass this type of legislation and under the supremacy clause that makes federal law supreme,” he said.

Pennsylvania Governor Ed Rendell, a Democrat, blasted the lawsuit, saying: “It’s a waster of taxpayer money and it’s nothing more than political grandstanding,” he told reporters.

Several Democratic governors released statements in support of the healthcare reform bill.

States have also cited the 10th Amendment of the Constitution, which states that “powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states,” as proof that the U.S. government cannot set their healthcare laws.

In addition to the pending lawsuits, bills and resolutions have been introduced in at least 36 state legislatures seeking to limit or oppose various aspects of the reform plan through laws or state constitutional amendments, according to the National Conference of State Legislatures.

So far, only two states -- Idaho and Virginia -- have enacted laws, while an Arizona constitutional amendment is seeking voter approval on the November ballot. But the actual enactment of the bill by President Barack Obama could spur more movement on the measures by state lawmakers.

Tea Party groups in Ohio planned to unveil a proposed constitutional amendment later on Monday aimed at shielding the state’s residents from “financial burdens and individual mandates” related to the federal healthcare changes.

As is the case on the Congressional level, partisan politics is in play on the state level, where no anti-healthcare reform legislation has emerged in Democrat-dominated states like Illinois and New York, according to the NCSL.

Florida Attorney General Bill McCollum, a Republican candidate running for governor, said the mandate would cost Florida at least $1.6 billion in Medicaid alone.

All states would receive extra funding to cover Medicaid costs, which are expected to rise under the reform, including 100 percent federal coverage for new enrollees under the plan through 2016.

Medicaid is the healthcare program for the poor jointly administered by the states and federal government.