International terrorism: Perpetrated by individuals and/or groups inspired by or associated with designated foreign terrorist organizations or nations (state-sponsored).
--for example, the December 2, 2015 shooting in San Bernardino, CA, that killed 14 people and wounded 22 which involved a married couple who radicalized for some time prior to the attack and were inspired by multiple extremist ideologies and foreign terrorist organizations.
Domestic terrorism: Perpetrated by individuals and/or groups inspired by or associated with primarily U.S.-based movements that espouse extremist ideologies of a political, religious, social, racial, or environmental nature.
--for example, the June 8, 2014 Las Vegas shooting, during which two police officers inside a restaurant were killed in an ambush-style attack, which was committed by a married couple who held anti-government views and who intended to use the shooting to start a revolution.
Stanford University Encyclopedia of Philosophy
The Foreign Relations of the United States series presents the official documentary historical record of major U.S. foreign policy decisions and significant diplomatic activity. The series, which is produced by the Department of State's Office of the Historian, began in 1861 and now comprises more than 450 individual volumes. The volumes published over the last two decades increasingly contain declassified records from all the foreign affairs agencies
The Global Terrorism Database (GTD) is an open-source database including information on terrorist events around the world from 1970 through 2017