Exclusive: Sen. John Walsh responds to revelations that he plagiarized Army War College paper

Facing a charge of plagiarism during his time at the Army War College, Montana Democratic Sen. John Walsh tells Yahoo News he was not formally diagnosed with PTSD upon returning from an Army deployment in Iraq, but says a doctor prescribed medication for symptoms of stress and anxiety. Walsh initially pointed to PSTD as a reason for plagiarizing in the paper, which borrowed text from several sources. Walsh says it was an isolated incident.