Chinese President Xi Jinping. (Pool photo/European Pressphoto Agency)

CHINA’S AUTHORITARIAN system has in the past few years tolerated a narrow space — a kind of gray zone — for some lawyers and activists to defend human rights, case by case. It became known as the rights defense movement and included appeals to China’s existing laws, as well as shrewd use of the Internet to expose the plight of victims. Despite the overarching power of the party-state and its intolerance of dissent, the Chinese authorities permitted these lawyers and activists to function, often because they were devoted to individual petitioners and didn’t seem to threaten the survival of the regime.

A wave of arrests and detentions over the past week points to a sudden closure of even this narrow space. In a nationwide sweep, as of Wednesday, police had detained and interrogated at least 159 human rights lawyers, activists and their relatives in 24 cities and provinces, according to a Hong Kong group that monitors human rights and rule of law in China. Some 10 remain in custody, and the whereabouts of 14 are unknown. The unusually wide crackdown appears to signal that the authorities will no longer tolerate these defenders of human dignity.

Typically, the lawyers disappeared suddenly. One prominent human rights lawyer, Wang Yu, returned home July 9 after dropping off her husband and son at the airport. She sent a text message to friends saying that the Internet connection and power at her home had been cut off. She sent another message saying that people were trying to break in. She has not been heard from since.

The sweep was accompanied by reports in the Chinese state media that the lawyers were conspiring, somehow, to create illegal protests and that the victims they were representing were secretly fomenting dissent. At first, the crackdown appeared to be focused on Fengrui, a law firm that defended many petitioners who had grievances over things such as land disputes. The firm was described in a report by the People’s Daily on Saturday as a “major criminal organization.”

But Fengrui was not the only target and others in the rights defense movement were detained and questioned in recent days. The crackdown appears to be the first since China approved a new national security law giving enhanced powers to the Ministry of State Security. It signifies a fresh assertion of control by President Xi Jinping, who seems to have little inclination to allow any alternative to the Communist Party’s stranglehold on power.

China is the only nation in the world that keeps a Nobel laureate, Liu Xiaobo , a courageous exponent of democracy, in prison. This crackdown is sweeping up many people who are less well known, but their struggle is no less vital. The rights defense movement existed in a sort of twilight zone, tolerated but not approved nor prohibited. Certainly, this is no substitute for a state based on rule of law. But it had value for China’s people, and suffocating it will be another loss — imposed from above.