This morning, President Barack Obama announced his decision to nominate Second Circuit Court of Appeals Judge Sonia Sotomayor to fill the seat on the Supreme Court being vacated by Justice David Souter, who has announced his retirement.  If confirmed, Sotomayor will represent an important vote on a variety of legal issues, including the scope and application of our nation’s environmental laws.

In 2007, Sotomayor authored the Second Circuit opinion in Riverkeeper v. EPA, holding that the Environmental Protection Agency could not rely on cost-benefit analysis in determining the “best available technology” required to minimize nuclear power plants’ cooling towers’ impacts on aquatic life.  475 F.3d 83 (2007).  Riverkeeper arose under the Clean Water Act, but it follows a diverse line of cases on whether agencies can base environmental decisions on cost-benefit analysis when the underlying statute is silent.  Last year, the Supreme Court reversed this opinion, with Justice Souter in the three-member dissent.

In US v. Giordano, a non-environmental case, Sotomayor rejected an attempt to limit Congress’s regulatory power under the Commerce Clause, holding that a national telephone network was an instrumentality of interstate commerce even if the calls in question occurred within a single state.  442 F.3d 30 (2006).  In recent years, a number of federal environmental laws, including the application of the Clean Water Act to “isolated” wetlands and the use of the Endangered Species Act to protect purely intrastate species, have been challenged as exceeding Congress’ commerce powers, leading to a 2007 Supreme Court opinion that set forth a new test for federal wetlands protections.  The Obama administration recently expressed support for legislative clarification of the scope of CWA jurisdiction.

If her opinions in Riverkeeper and Giordano are any guide, it is likely that Sotomayor, if confirmed, will bring to the Supreme Court a deference to Congressional determinations requiring environmental protection, even in the face of potentially high economic costs.  She also may hold a relatively broad view of Congress’ interstate commerce authority, which may stymie further attempts to challenge environmental statutes on those grounds.

• Further reading: Obama Supreme Court Pick Has Small but Solid Record on Environmental Rulings (Grist)