Ninth Circuit Backs Washington's Climate Law Against Commerce Clause Challenge

The Ninth Circuit upheld Washington's Climate Commitment Act against a dormant Commerce Clause challenge by PacifiCorp.

On August 7, 2026, the Ninth Circuit Court of Appeals affirmed the dismissal of PacifiCorp’s lawsuit challenging Washington State’s Climate Commitment Act (CCA). The utility company had argued that enforcement of the CCA by the Department of Ecology violated the dormant Commerce Clause by discriminating against out-of-state entities.

The court disagreed, emphasizing that PacifiCorp failed to plausibly allege the State’s decarbonization rules were applied in a discriminatory manner. It noted that electric utilities like PacifiCorp and independent power plant owners are not similarly situated, which undermined the discrimination claim. Additionally, the court found that the CCA did not impose impermissible burdens on interstate commerce.

PacifiCorp also raised an equal protection challenge, which the Ninth Circuit rejected. The company could not negate Washington’s rational basis for the law, which is to balance the rising cost of energy against the state's environmental goal of reducing greenhouse gas emissions.

This ruling reinforces state authority to implement climate regulations without infringing constitutional commerce protections, a position underscored by environmental law experts. As explained by a professor of environmental law, "The Ninth Circuit's decision underscores the importance of state autonomy in implementing climate policies that address local environmental concerns without violating constitutional principles."

Washington’s CCA is a key policy tool in its broader strategy to decarbonize the economy through a cap-and-invest program. This decision thus sets an important precedent for similar legal conflicts involving state climate initiatives and interstate commerce challenges.