The Chinese government is once again cracking down on freedom of expression. Authorities in Beijing have detained writer Liu Xiaobo, one of the signatories to a document published online recently calling for reforms to China's one-party system.

Constitutional scholar Zhang Zuhua was temporarily held for questioning. Some signatories had their homes searched or were questioned and placed under surveillance even before the document was published. Deputy chairman of the writers' group Independent Chinese PEN Jian Qisheng was interrogated by police for 2 hours.

Charter '08, as the document is known, was signed by more than 300 prominent scholars, writers, and rights activists from around China. "Among the great nations of the world," the Charter states, "China, alone, still clings to an authoritarian political way of life. As a result, it has caused an unbroken chain of human rights disasters and social crises, held back the development of the Chinese people, and hindered the progress of human civilization."

The Charter calls for upholding the rule of law, enacting democratic reforms, and protecting human rights. Without such reforms, the Charter warns, social tensions are likely to rise within China.

"The United States," said U.S. State Department spokesman Sean McCormack, "is deeply concerned by reports that Chinese citizens have been detained, interrogated, and harassed as they prepared to commemorate Human Rights Day and the 60th anniversary of the adoption of the Universal Declaration of Human Rights."

He noted particular concern about the well-being of Liu Xiaobo, who remains in the custody of authorities. The United States "call(s) on the government of China to release Liu Xiaobo and cease harassment of all Chinese citizens who peacefully express their desire for internationally recognized fundamental freedoms."