The Supreme Court is making it difficult for utility companies to challenge costly, long-term energy supply contracts negotiated during the West Coast energy crisis seven years ago.

The justices said in a 5-2 decision Thursday that the contracts must be presumed to be just and reasonable, absent serious harm to the public interest.

Writing for the majority, Justice Antonin Scalia nonetheless ruled in favor of the utilities on one point, saying the Federal Energy Regulatory Commission must provide a more complete explanation of why it upheld the agreements.

The presidentially appointed commission said the agreements were not contrary to the public interest.