Pu has been involved in a number of high-profile freedom of speech cases in China, defending dissident writers and journalists. In 2004, he defended writers Chen Guidi and Wu Chuntao. The couple was facing libel charges for their portrayals of local Communist Party official Zhang Xide in their best-selling book "A Survey of the Chinese Peasants." The case—and Pu's litigation in court—garnered international attention. Philip Pan of the "Washington Post" wrote that "by the time finished his cross-examination, the mood in the courtroom had begun to change. When the trial ended three days later, ... it seemed as if Zhang – and the Communist Party itself – were the ones on trial." The same year, Pu won a landmark victory on behalf of the "China Reform" magazine, which was similarly facing libel charges for its critical reporting on a real estate developer. The court decided in the magazine's favor, ruling that journalists are entitled to legal immunity on the condition that their stories are based on a reasonably believable source, rather than hearsay or fabrication.