China is threatening to detain Americans living in China in the latest bout of hostage diplomacy. You may remember China detained two Canadians, Michael Kovrig and Michael Spavor in retaliation for Canada arresting Huawei CFO Meng Wanzhou. Now the US has detained several Chinese scholars who allegedly hid ties to the Chinese military and were working with the Chinese consulate in Houston to commit espionage. The State Department has warned Americans not to travel to China because they risk arbitrary arrest and exit bans.