On Tuesday, the Supreme Court dealt a blow to President Obama’s signature climate change initiative by halting the administration’s effort to reduce pollution from coal-fired power plants until all legal challenges were heard.

Designed to cut U.S. emissions by 32 percent by 2030, the plan put emphasis on a shift to renewable energy, and it was the key element of the historic climate change agreement reached in December 2015 at the United Nations climate negotiations held in Paris, which involved 195 nations.  With the Supreme Court’s decision, it appears the United States will have difficulty holding up its part of that deal.

A group of 29 states, utilities and coal companies have sought to block the proposal in the courts, arguing that the plan was an infringement on states’ rights.  An initial attempt to halt implementing the plan until legal challenges were heard was thrown out by a U.S. appeals court in Washington in January.  However, the Supreme Court voted 5-4 to suspend the plan pending the outcome of the current litigation.  The Supreme Court was divided along ideological lines, with conservative justices all supporting the stay while the liberal justices opposed the stay.

As a result of the Supreme Court decision, the Environmental Protection Agency must halt enforcement of the Clean Power Plan until the U.S. Court of Appeals for the D.C. Circuit decides on the merits of states lawsuit against it.  Oral arguments are set for early June.   Even if the Clean Power Plan is upheld in the lower court, it could not be implemented until the Supreme Court has had the final word.

Under the Clean Power Plan, individual states were required to submit their proposals on how to meet the CO2 restrictions by September this year.  That date will now be missed.  And, it appears unlikely that all legal questions over the future of the Clean Power Plan will be resolved before President Obama’s leaves office next January.

The Supreme Court’s action marks the second time recently that an executive action taken by the Obama administration has been stalled in the courts.  President Obama’s plan to forestall potential deportation for more than 4 million illegal immigrants has also been blocked pending the high court’s review.  Oral arguments on that issue are likely in April with a decision expected by June.