Investigators found odd, little pills buried in the pockets of Hamas terrorists who attacked Israel on Oct. 7. They were later identified as the drug Captagon, a powerful, synthetic stimulant. Captagon gained international notoriety in 2015 when it was discovered to be used by ISIS fighters to suppress fear and fatigue prior to carrying out terrorist operations. Now, because it’s cheap, as well as easy to make and smuggle, Captagon and its counterfeits are likely to remain a favorite tool of extremist militant groups to enhance their soldiers’ violent tendencies. Some reports have even labeled Captagon as “the jihadists’ drug,”...