Are Prisons Conveyor Belts to Jihad?

As the United States and its coalition partners continue to squeeze ISIS out of its remaining territory in Iraq and Syria, more and more foreign fighters are returning to their home countries. This migration from the battlefield to the hometown is causing great concern among Western counterterrorism authorities. The question on everyone's mind is how long before the returning jihadists unleash an attack on their own countries. 

Not very long, according to a new study on terrorism and political violence. Within one year, the study found, and in some cases as little as months, returning fighters attempted a terrorist attack in their home countries.