Enter Xu Zhangrun. A fifty-six-year-old professor of constitutional law at Beijing's prestigious Tsinghua University, Xu is well known in Beijing as a moderate and prolific critic of the government's increasing embrace of authoritarianism. The government is, of course, adept at marginalizing such voices. As a result, Xu and his supporters are unknown to the vast majority of Chinese people. That makes it hard for public intellectuals to effect change. But they perform another, important function: reflecting the Zeitgeist of an era.