In this decision, the Court evaluated the authority of the Federal Energy Regulatory Commission (FERC) to amend wholesale electricity agreements pursuant to the Mobile-Sierra Doctrine. The decision has wide-reaching implications for FERC's authority under the Federal Power Act (FPA), and, by extension, its authority under the Natural Gas Act (NGA). What is the Mobile-Sierra Doctrine? Corp . and FPC v. Sierra Pacific Power Co ., the Court held that an electricity or natural gas contract, once approved by FERC, cannot be changed pursuant to a unilateral request of one of the parties absent a showing that such a change is in the public interest. The Doctrine in the Market-Based Rate Environment: FERC and Circuit Court Decisions in the Snohomish Matter

As described above, FERC's application of the Mobile-Sierra Doctrine has evolved and some commentators might suggest that the Doctrine has become a less significant hurdle to FERC review/amendment of rate agreements in recent years.
In June of 2008, the U.S. Supreme Court issued a decision that has important implications for the authority of the Federal Energy Regulatory Commission (FERC) to review wholesale electricity and natural gas contracts under what is known as the "Mobile-Sierra Doctrine." The Doctrine mandates that FERC will not abrogate contracts (including wholesale natural gas and power contracts as well as transmission agreements) between private parties absent a showing that a change is necessary in the public interest. This report reviews the Mobile-Sierra Doctrine and discusses a recent Supreme Court decision that evaluated the Doctrine and FERC's review role as set forth in the Federal Power Act in the context of market-based rates.