• The professor versus Xi Jinping.

A legal scholar in Beijing, Xu Zhangrun, has delivered the fiercest denunciation yet of President Xi Jinping from a Chinese academic. It comes as a vaccine scandal and trade battles with Washington have emboldened critics to question Mr. Xi’s sweeping control.

Professor Xu challenged political taboos: urging the government to overturn its condemnation of the pro-democracy protests that erupted in Chinese cities in 1989 and ended after the Tiananmen Square crackdown, and calling on Chinese lawmakers to reverse the vote that abolished a two-term limit on Mr. Xi’s presidency.

The professor, who is listed as being a visiting scholar in Japan, did not answer messages and phone calls. His future treatment may indicate whether Mr. Xi will tolerate criticism.