Today, on October 31, 2011, the Supreme Court of the United States denied (pdf) review of a constitutional challenge to water delivery regulations regarding the Central Valley Project and California State Water Project intended to protect the threatened delta smelt. The petition for writ of certiorari was filed by the Pacific Legal Foundation on behalf of Stewart & Jasper Orchards, and asserted that application of the Endangered Species Act (ESA) to the delta smelt, a noncommercial fish that is only found in California, is an unconstitutional exercise of congressional power under the commerce clause of the U.S. Constitution. The government opposed (pdf) the petition by asserting, among other things, that the ESA is a comprehensive regulatory statute bearing a substantial relation to interstate commerce.

Some found it unsurprising that the Supreme Court did not take the case because there is no split in the federal courts of appeal on the issue. To date, the Supreme Court has declined to review constitutional challenges to the ESA on six different occasions.

In late March, the U.S. Court of Appeals for the Ninth Circuit held that the water delivery regulations did not violate the commerce clause. The court concluded that the protection of endangered and threatened species (including wholly intrastate species such as the delta smelt) bears a substantial relation to interstate commerce. The petition for writ of certiorari was filed on June 22, 2011.