The Obama administration is backing $675,000 in damages a Massachusetts student must pay the Recording Industry Association of America for file sharing 30 songs. The Justice Department, where President Barack Obama has tapped five former RIAA lawyers to serve, said copyright infringement “creates a public harm that Congress determined must be deterred.” The administration’s court filing Tuesday is the latest in the case of Joel Tenenbaum, a Boston University graduate student who was the nation’s second defendant to go to trial against the RIAA on file sharing charges. Most of the 30,000 civil cases the music industry has brought have settled out of court. After the July verdict in a Boston federal court, Tenenbaum’s...