Halfway through his first five-year term, U.N. Secretary General Antnio Guterres is becoming defined by his silence on human rights - even as serious rights abuses proliferate. Numerous governments have voiced concerns about China's detention of 1 million Turkic, mainly Uighur, Muslims for forced indoctrination. Yet Guterres has not said a word about it in public. Instead, he praises China's development prowess. Guterres has also repeatedly declined to exercise his authority to establish fact-finding missions into egregious rights violations, such as Saudi Arabia's murder of Post contributing columnist Jamal Khashoggi, the use of chemical weapons in Syria, and the murder of two U.N. sanctions monitors in Congo. Apart from his spokesman's feeble appeal to the United States to fulfill its legal obligations as host for the United Nations, Guterres has stayed silent on the Trump administration's revocation of a visa for the International Criminal Court's chief prosecutor over possible investigations of U.S. torture in Afghanistan. There is no doubt that Guterres is a skilled and conscientious diplomat, but his decision to suppress his voice on human rights, especially as civilians are targeted in armed conflicts, is misguided. For more than two years, Guterres offered excuses for not publicly defending human rights. He wanted to focus on internal reforms. He needed to stabilize relations with Trump. But today's crises are too acute, the civilian victims too numerous, for Guterres to reduce his job to mediator in chief.