In just two months, Yale graduate Edward Kuperman went from being praised by Chinese state media to being bombarded by public accusations that he was a spy. It began with a June 18 article from state news agency Xinhua, in which he was described as an eager 24-year-old sinophile who made the unconventional choice of spurning China’s eastern metropolises to live in Dunhuang, an oasis in the country’s northwestern Gansu province. His interest in China started with a Chinese language class in...