Why can't Professor Li Kaiyuan return to the motherland?

It is a personal choice for Professor Li Kaiyuan not to return to China. Li Kaiyuan, 1982, graduated from the history department of Peking University and stayed as a teacher. Doctor of Literature, University of Tokyo; Professor of Humanities Department, Shihushi University; Part-time researcher, China Ancient History Research Center, Peking University; Visiting scholar of Peking University Institute of Humanities and Social Sciences.