text: Insurgency Prerequisites and Fundamentals
  planning. Commanders and staffs must understand the connections between a physical environment and its
  effect on an insurgency. (See chapter 2 for more information on a physical environment.)
  Fifth Dynamic—External Support
  4-62. Historically, insurgencies are less likely to succeed without some form of external support. This
  support can be in the form of—
  * Moral support.
  * Political support.
  * Resources, such as money, weapons, food, advisors, training, and foreign fighters.
  * Sanctuary, such as secure training sites, operational bases over a border, or protection from
  extradition.
  4-63. Governments providing support to an insurgency normally share interests or a common ideology
  with the insurgency. Ethnic enclaves or diasporas in third-party countries can provide significant support,
  even if a country’s government is not actively supporting an insurgency. For example, global diasporas can
  provide significant resources for an insurgency, even if no government is providing active support. (See
  FM 3-05, chapter 2, for more information on unconventional warfare.)
  4-64. +However, with external support comes a degree of dependency on that support. Limiting access to
  external support is a possible means of influencing or changing the actions of an insurgency. Limiting
  external support provides one means to affect an insurgency indirectly. External support can help to shape
  an insurgency and the outcome of an insurgency. In the case of the insurgency in Sri Lanka, external
  support was essential to the success of the Liberation Tigers of Tamil Eelam. Large diasporas provided the
  Liberation Tigers of Tamil sanctuary and resources. This allowed them to gain dominance over other
  insurgent groups and to wage a long and bloody insurgency against the government of Sri Lanka.