In counterterrorism, the most dangerous intelligence failure is not the inability to detect an imminent attack, but the failure to understand the adversary’s doctrine, operational networks, strategic patience, and capacity to strike long before the threat becomes visible.The Axios report on a U.S. intelligence memorandum warning of “advanced” Iranian plots to assassinate American officials abroad reveals only the tip of the iceberg. The problem extends far beyond what has been disclosed. Neither the CIA, the FBI, the Department of Homeland Security (DHS), nor the National Counterterrorism Center (NCTC) possesses an adequate understanding of Shiite terrorism.