Dive Brief:

• New York Attorney General Eric Schneiderman is leading a coalition of 18 states and some cities and counties in defense of the Clean Power Plan. The group has filed a motion to intervene to defend the federal greenhouse gas plan, Greenwire reports. 
• They are squared off against 26 states who have filed a variety of legal challenges.
• Only six states have so far remained neutral: Alaska, Idaho, Mississippi, Nevada, Pennsylvania and Tennessee.

Dive Insight:

It's not often a regulatory package divides the nation so starkly, but the EPA's carbon regulations have done just that. 

Nearly every state has jumped into the legal battle over the Obama administration's Clean Power Plan, an unprecedented level of interest in federal climate rules. "I can't recall a Clean Air Act rule, or other EPA rule, that had 44 states in the mix," Joe Stanko, an attorney at Hunton & Williams, told Greenwire, with the news outlet describing the expanding legal fight a "brawl."

The more than two dozen states challenging the rule "are the most ever to challenge an EPA rule and, as far as I know, any federal action," said Bracewell & Giuliani attorney Jeff Holmstead.

Through a variety of legal challenges – the largest includes 24 states led by West Virginia – some 26 states have filed lawsuits to block the Clean Power Plan.

In total, states opposed to the rule include:  Alabama, Arizona, Arkansas, Colorado, Florida, Georgia, Indiana, Kansas, Kentucky, Louisiana, Michigan, Missouri, Montana, Nebraska, New Jersey, North Carolina, North Dakota, Oklahoma, Ohio, South Carolina, South Dakota, Texas, Utah, West Virginia, Wisconsin and Wyoming. 

The 18 states filing to defend the plan include: California, Connecticut, Delaware, Hawaii, Illinois, Iowa, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Mexico, New York, Oregon, Rhode Island, Vermont, Virginia and Washington. The District of Columbia, Chicago, New York City and Philadelphia have also signed on.

“Climate change represents an unprecedented threat to the environment, public health, and our economy.  We no longer can afford to respond to this threat with denials or obstruction,” New York AG Schneiderman said in a statement. "We are committed to aggressively defending the Clean Power Plan to ensure progress is made in confronting climate change.”

And on the other side:

"The Clean Power Plan is one of the most far-reaching energy regulations in this nation’s history," said West Virginia Attorney General Patrick Morrisey. "West Virginia is proud to be leading the charge against this Administration’s blatant and unprecedented attack on coal.”

Beyond rhetoric, Greenwire points out the reason for the divide: The 18 states supporting the rule make up only about 12% of the emissions reductions required by the CPP, and include a couple of states not covered by the rule (Vermont and Hawaii; Alaska has remained neutral). States challenging the plan make up about 80% of the required reductions.