WASHINGTON – A legal war among 23 states erupted Wednesday over the federal government’s attempt to relax air pollution regulations.

Nine states are taking on 14 states, including Maine, that want to block new federal rules relaxing pollution requirements for power plants, refineries and manufacturers. The battle falls along partisan lines.

Virginia’s attorney general, Jerry Kilgore, a Republican, led his state and Alabama, Alaska, Arkansas, Kansas, Nebraska, North Dakota, South Dakota and Utah in asking to intervene in a case filed in the U.S. Court of Appeals for the District of Columbia.

The 14 states last week filed suit to stop the Environmental Protection Agency from implementing new Clean Air Act rules that make it easier for older plants to make upgrades without having to install more pollution controls.

The nine states argued in court papers filed Wednesday that the lawsuit “will have a negative effect on them” by increasing the cost of enforcing air pollution cases, limiting enforcement options and “frustrating” industry’s ability to make efficiency and cost-saving improvements.

“The changes at issue in this case will have a substantial impact on both the states’ costs of enforcing the act’s requirements and the flexibility that the states enjoy in enforcing those requirements,” Kilgore wrote on behalf of the attorneys general.

All but one of the attorneys general representing the nine states seeking to intervene in the case are Republicans; Mike Beebe of Arkansas is the sole Democrat.

All but two of the attorneys general representing the 14 states that filed suit against EPA are Democrats; Peter Heed of New Hampshire and Mike Fisher of Pennsylvania are Republicans.

Filing the suit to block the new rules from going into effect Dec. 26 were New York, California, Connecticut, Illinois, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New Mexico, Pennsylvania, Rhode Island, Vermont and Wisconsin. They were joined by a number of cities, including New York, San Francisco, and Washington, D.C.