Canada's resolve to uphold its no-ransom policy for citizens being held captive was put to the test in April when Philippine Islamist group Abu Sayyaf made good on its threats to execute a Canadian hostage. The group had been holding Canadian national John Ridsdel since it captured him and three other people in September 2015. After Canada refused to proffer a ransom, the 68-year-old businessman's severed head was discovered in the street on the Philippine island of Jolo, an Abu Sayyaf stronghold. The militants made their point: They're not bluffing. Now, less than a month later, the group is threatening to execute another hostage. The question is, will the nations whose citizens are being held negotiate with the terrorists or pay a ransom?...