The extraordinarily harsh sentence, which included the confiscation of Mr. Tohti’s assets, reflected the Chinese Communist establishment’s extreme sensitivity to any dissent, and especially to the Uighur insurgency in the Xinjiang region of western China. On Thursday, Chinese state media reported that a series of bomb blasts and violent clashes on the previous weekend left 50 dead and many injured in the region.

The Uighurs are Turkic-speaking Muslims who identify culturally and ethnically with the Central Asian nations that border Xinjiang. The region came under Chinese rule in the 18th century and was incorporated into Communist China in 1949; since then, vast numbers of Han Chinese have moved in, creating strong frictions with the local population.

Mr. Tohti, 44, was a strong critic of Chinese assimilation policies, but also a voice of moderation. He cited figures to show that investment in the region was going mainly to newly arrived Han, and he criticized restrictions on religious practice, but he never advocated secession or violence.

In an interview shortly before he was detained in January, he suggested that he was being punished less for his championship of the Uighurs than for revealing the failure of government policies. “Sometimes I feel like the government is more afraid of people telling the truth than they are of the protests and violence,” he said.

To Bomb or Not to Bomb

History will have the last word on whether Mr. Obama’s decision to bomb terrorist bases inside Syria was right. But once the Islamic State barbarians threatened to overrun Iraq and began publicly decapitating American and British hostages, the president’s hand was forced.

The question was whether by identifying the Islamic State, also known as ISIS or ISIL, as the premier “network of death” in the region, Mr. Obama was in effect bolstering some of the competing villains. It was not clear, for example, how American fighters could operate in Syria without at least tacit consent from the Syrian government. One Syrian diplomat boasted in a pro-government newspaper that “the U.S. military leadership is now fighting in the same trenches with the Syrian generals, in a war on terrorism inside Syria.”

This being the Middle East, the complications did not stop there. America’s Arab allies in the campaign against the Islamic State — Bahrain, Jordan, Qatar, Saudi Arabia and the United Arab Emirates — are all monarchies that survived the Arab Spring. Then, Washington had appeared to be moving away from traditional alliances with autocratic Middle Eastern leaders, but now they were again being called essential partners in an existential struggle.