For two years, the Canadian men have been held in separate prisons in northern China, largely cut off from the rest of the world. They have been accused of espionage, without evidence, and forced to go months without visits from diplomats. They have waited as their cases have meandered through China’s opaque legal system, despite calls around the world for their release.

The men — Michael Kovrig, a former diplomat, and Michael Spavor, an entrepreneur — were once relatively low-profile expatriates working in Asia. They have now become symbols of the consequences of Beijing’s increasingly aggressive foreign policy, their fates seemingly intertwined with the future of China’s tumultuous relationships with Canada and the United States.

China has made clear that it remains angered by Canada’s decision in December 2018 to detain Meng Wanzhou, a prominent Chinese technology executive, at the request of American prosecutors. The detentions of Kovrig and Spavor shortly thereafter — two years ago on Thursday — were widely perceived as retribution.