Why has China released detained Australian journalist Cheng Lei?

The arrival of Cheng Lei back in Melbourne is clearly a moment of celebration for the Chinese Australian journalist and her family from whom she has been separated for over three years. But it would also seem to be a triumph for Australian diplomacy, as well as a signal of China’s serious intent to improve Australia-China relations. For some time, Cheng’s incarceration has remained a sticking point for Canberra in a more reasonable relationship emerging between the two sides. Although born in China, Cheng has been an Australian citizen for years, having migrated to Melbourne with her parents at the…