By KEVIN SACK

c.2010 New York Times News Service

ATLANTA - Reflecting the bitter partisan divide over health care, governors in at least six states are at war with attorneys general from the other political party about whether to join litigation challenging the new federal health insurance mandate.

In four states - Colorado, Michigan, Pennsylvania and Washington - Democratic governors are criticizing Republican attorneys general for joining the lawsuit over their objections. On Friday, those governors wrote to the federal attorney general, Eric H. Holder Jr., to offer their assistance in defending the new law against the litigation filed by their own states.

In Georgia and Mississippi, meanwhile, Republican governors are chafing at the reluctance of Democratic attorneys general to join the lawsuit on their behalf. They are exploring ways to circumvent their states' top legal officers and join the case anyway.

The disputes carry a heavy overlay of election-year politics. Not only are Democrats and Republicans supporting the positions of their national parties, but three of the attorneys general are running to succeed the governors they are battling, and a fourth is considering a race in 2012. Each faces a primary that requires appealing to the party base.

Here in Georgia, Attorney General Thurbert E. Baker is competing in a crowded field for the Democratic nomination for governor. On Wednesday, he formally declined Gov. Sonny Perdue's request that the state join the lawsuit, saying it had "no legal merit."

"I concluded that any litigation would fail," Baker said in an interview, "and that it would cost the taxpayers of Georgia significant amounts of hard-earned taxpayer dollars."

Baker cited constitutional provisions that give federal laws supremacy over state actions. "This is not a tough legal question," he said.

Perdue, a Republican who will leave office in January because of term limits, announced Thursday that he would deputize a special attorney general to file a lawsuit for the state. Baker does not dispute the governor's authority to do so.

Perdue's spokesman, Bert Brantley, said that many lawyers had volunteered to handle the case pro bono and that mail and calls from constituents were running heavily against the new law.

Twelve attorneys general, all but one of them Republican, joined a lawsuit filed Tuesday in federal court in Florida by Bill McCollum, a Republican attorney general who is running for governor. The attorney general of Virginia, also a Republican, has filed a separate challenge.

Their primary claim is that the Democratic-controlled Congress and President Barack Obama exceeded their constitutional authority in enacting legislation last week that will eventually require most Americans to obtain health insurance. McCollum called the mandate, which takes effect in 2014, "an unprecedented encroachment on the liberty of the American people."

Attorneys general are charged with representing the governor and executive branch agencies, but also may initiate and intervene in litigation in the interest of the citizenry. It is not uncommon, given that governors and attorneys general are elected independently and can be from opposing parties, that they clash over questions of authority.

In Michigan, Gov. Jennifer M. Granholm, a Democrat who cannot run again this year because of term limits, wrote a blistering letter last week to Attorney General Mike Cox, a Republican who announced on his Web site that "Michigan has joined" the health care lawsuit.

Granholm, a former attorney general, chastised Cox for "speaking for the state of Michigan" and told him his stand was "directly contrary to the position of this administration."

She questioned whether he had the constitutional authority to supersede her own. And she directed him, as her lawyer, to assist in the defense of the case, asking his office in essence to work against itself. Cox, who is running in a competitive primary to succeed Granholm, said he was obligated to do so.

"I'm perfectly willing to let her exercise her option of being wrong and being represented while she does so," Cox said. "The reality is that the federal court recognizes the attorney general as the voice of the state in federal litigation."

The thrust and parry has been much the same in Pennsylvania. Gov. Edward G. Rendell, a Democrat who is also barred from seeking re-election this year because of term limits, urged Attorney General Tom Corbett to withdraw from the lawsuit. "It's hard to imagine that you take this action on behalf of those who may be sick or have a chronic illness but are uninsured," Rendell wrote to Corbett, the leading Republican running to replace him.

Democrats who control of the state's House of Representatives threatened to slash Corbett's budget, but the Republicans in charge of the state Senate said they would not let that happen.

In Washington, Gov. Christine Gregoire, a Democrat, said she was open to using the state budget process to block Attorney General Rob McKenna, a Republican, from spending money on the suit.

"I don't know who he represents," Gregoire said at a news conference last week. "He doesn't represent me."