CHEYENNE, Wyo. — Matt Mead, the governor of Wyoming, the nation’s leading coal-producing state, fiercely opposes President Obama’s climate change regulations, which could shutter hundreds of coal plants and deeply wound his state, one of 27 that are suing to block the plan.

Nevertheless, Mr. Mead, a Republican, has ordered his top environmental officials to prepare to comply with the president’s effort, known as the Clean Power Plan — to prepare for a future in which Mr. Obama’s climate change rules prevail and the country’s coal market is nearly frozen. Wyoming is one of at least 20 states that are moving forward with efforts to comply with the rules or to analyze alternative plans. Several of these states are also suing to stop the rules, according to experts who track state climate change policy.

“Obviously we’re suing and going to fight,” Mr. Mead, a former United States attorney for Wyoming, said in an interview in his office here. “But from my court experience, I know you have to prepare not to win.”

Mr. Obama’s ambitious climate change plan is in legal limbo. The Supreme Court has ordered the Environmental Protection Agency to halt the plan until after the states’ lawsuit is resolved. The case will go before a federal court in September, but it is widely expected to be appealed to the Supreme Court and may not be decided until 2018.