"President Barack Obama's plan to use federal agencies, and the Environmental Protection Agency in particular, to drive his second-term climate change agenda might be in peril if he cannot fill vacant seats on the federal court that has jurisdiction over major national regulations, legal experts say."

"Obama is the first full-term president in more than a half century not to have appointed a single judge to the powerful U.S. Court of Appeals for the District of Columbia Circuit.

The court, considered the second most important in the nation, decides cases challenging agency regulations such as those involving the EPA's Clean Air Act and often serves as a feeder to the Supreme Court.

New York attorney Caitlin Halligan, Obama's first nominee to fill one of four vacant seats on the 11-judge bench, announced her withdrawal on Friday after Republicans twice blocked her nomination over concerns about a 2001 case in which she represented New York state and argued that gun manufacturers had created a "public nuisance" under state law."

Valerie Volcovici reports for Reuters March 25, 2013. [2]