In the republic of Dagestan, a brutal separatist insurgency has long fought against the Russian state. Now, as many as 5,000 Dagestanis have left to fight for the Islamic State. Why have so many answered the call? As part of our week-long series Inside Putin's Russia, special correspondent Nick Schifrin and producer Zach Fannin report, in collaboration with the Pulitzer Center on Crisis Reporting.
