ASIL Insights are brief, but footnoted, analyses of recent events and developments in international law. They appear a few times a month on the American Society of International Law website and are emailed to subscribers. The most recent Insight -- Special Tribunal for Lebanon Issues Landmark Ruling on Definition of Terrorism and Modes of Participation by Michael Scharf – is a commentary on the February 2011 interlocutory decision by that tribunal’s Appeals Chamber, listing three key elements in the customary international law definition of terrorism: (i) the perpetration of a criminal act...or threatening such an act; (ii) the intent to spread fear among the population; and (iii) a transnational element. According to Scharf, this is the first time an international tribunal has “authoritatively confirmed a general definition of terrorism under international law” and is likely to have “a momentous effect.”