A broad and powerful coalition of governors, attorneys general, coal companies, electric utilities and business groups such as the United States Chamber of Commerce will file suits contending that the rules, put forth under the 1970 Clean Air Act, represent an illegal interpretation of the law. They will also petition to delay implementation of the rule until the case is argued in federal court.

“The president’s illegal rule will have devastating impacts on West Virginia families, and families across the country,” Attorney General Patrick Morrisey of West Virginia said in a statement. Mr. Morrisey, whose home state’s economy is heavily dependent on coal mining, is expected to play a lead role in the multistate lawsuit.

States and companies may be hedging their bets.

In Georgia, Gov. Nathan Deal’s administration plans to sue the E.P.A. At the same time, the governor, a Republican, has also instructed his director of environmental protection, Judson H. Turner, to begin crafting a plan to comply with the rules.

“The governor of Georgia said to me, ‘Whatever action may be taken on the legal front, we’ll need to develop a plan that works for Georgia,’ ” Mr. Turner said. If Mr. Obama’s plan survives the legal challenge, Mr. Turner added, “we’ll have the confidence that we’ll put a plan for Georgia together that’s better than a federal plan.”

Similar dynamics are playing out in many other states that are suing over the rules, said Vicki Arroyo, the executive director of the Georgetown University Climate Center, which focuses on state-level climate policies.

“It’s really rare to find a state that just says, ‘Hell no,’ ” she said.

The rules assign each state a target for reducing its carbon pollution from power plants, but allows states to create their own custom plans for doing so. That rule is designed to encourage states to make major changes in their electric power sectors — for example, to shut down coal-fired power plants and replace them with wind and solar power. It is also designed to encourage states to enact so-called cap-and-trade systems, under which they would place a cap on carbon emissions and create a market for buying and selling pollution credits.

States have to submit an initial version of their plans by 2016 and final versions by 2018. States that refuse to submit a plan will be forced to comply with one developed by the federal government.