The U.S. Supreme Court has agreed to halt enforcement of federal carbon dioxide regulations until legal challenges to the rule are resolved.
The stay issued Tuesday evening is a blow to President Barack Obama's Clean Power Plan, which sets individual carbon dioxide reduction goals for each state.
Kentucky is one of 29 states and state agencies challenging the legality of the regulations. That lawsuit is still pending in the U.S. Court of Appeals for the D.C. Circuit, but the Supreme Court decision will effectively block the implementation of the rule until the lower court rules.
The 5-4 Supreme Court ruling is a victory for the rule's opponents. Kentucky, for one, had sought the stay in an attempt to get the litigation settled before the state invested time and money in developing a compliance plan for the rule.
Kentucky joined the lawsuit under former Attorney General Jack Conway, and current Attorney General Andy Beshear is continuing the state's involvement. In a statement, Beshear praised the Supreme Court's ruling.
"Kentucky's coal industry and miners have been decimated by guidelines that up until now they have not had the standing to challenge," he wrote. "Regardless of where you stand on these issues, the federal government must follow the law. The EPA guidelines simply are not allowed under the law."
The first deadline under the plan is in September; Kentucky's Energy and Environment Cabinet had already announced its intention to seek an extension, but the stay will likely push that deadline back even further. The first benchmark for carbon reductions is in 2022 under the current plan, with states' full compliance required by 2030.
The D.C. Circuit Court of Appeals will hear the case beginning on June 2, and whatever the outcome, it's likely it will be appealed to the Supreme Court.
This story has been updated.