The most significant discourse about serious threats to U.S. national security in the twenty-first century will likely concern the military capabilities and intentions of non state actors, acting either for themselves, for religious elites, or as surrogates for state sponsors. This preoccupation results not from any inordinate fear of “terrorism” but from a recognition of objective military and political realities. While prior to 1991 only the Soviet Union possessed the capacity to inflict catastrophic military destruction on the United States, today that threat is vested in terrorist cells and religious sects that seek to destroy the fabric of the United States through unconventional military and paramilitary means. The terrorist attacks of 11 September 2001 bear this out.
Terry, James P., "The Regulation of International Coercion" (2005). The Newport Papers. 25.