Benedetta Berti: The surprising way groups like ISIS stay in power

ISIS, Hezbollah, Hamas. These three very different groups are known for violence — but that’s only a portion of what they do, says policy analyst Benedetti Berti. They also attempt to win over populations with social work: setting up schools and hospitals, offering safety and security, and filling the gaps left by weak governments. Understanding the broader work of these groups suggests new strategies for ending the violence.