text: Chapter 4
  enhance an operational environment in ways favorable to friendly forces and occurs during competition,
  crisis, and armed conflict. While setting the theater occurs across each strategic context, its importance is
  greatest during competition because that is when the most time is available. Army forces must set the theater
  during competition to enable quick transitions during crisis and conflict, when time favors the aggressor.
  Army forces use military engagements, security cooperation, and other activities to assess and understand
  the current conditions within the theater and execute specific theater setting activities to enable joint forces
  and other unified action partners.
  4-14. Setting the theater requires a comprehensive approach among unified action partners and bilateral or
  multilateral diplomatic agreements that allow U.S. forces access to ports, terminals, airfields, and bases in
  the area of responsibility (AOR) to support future operations. This includes but is not limited to theater
  opening; reception, staging, onward movement, and integration (RSOI); establishing networks; classifying
  routes; and other operational activities that set the conditions for operations in the AOR. Information
  activities are a significant part of setting the theater. They enable decision making, protect friendly
  information, inform domestic and international audiences, and influence foreign audiences, while helping to
  counter adversary information warfare.
  4-15. Setting the theater is a continuous activity for all staff sections and warfighting functions. It involves
  significant sustainment, air and missile defense (AMD), engineering, information collection, intelligence,
  and communications focused on setting conditions to counter known or potential threats to U.S. interests
  across the AOR. All warfighting functions, functional areas, and branches that comprise staffs and commands
  conduct preparation of the operational environment to address unique considerations for setting the theater
  within their respective areas of expertise (for example, civil preparation of the environment and joint
  intelligence preparation of the operational environment). (For more information about the land component's
  roles and responsibilities for setting the theater in conflict, refer to JP 3-31 and JP 3-35. For additional
  information about the subordinate Army tasks and activities associated with setting the theater, refer to
  ATP 3-93 and FM 4-0. See paragraphs 4-61 and 4-62 of this publication for considerations unique to theater
  armies and Chapter 7 for theater-setting considerations in a maritime environment.)
  BUILD ALLIED AND PARTNER CAPABILITIES AND CAPACITY
  4-16. Army forces fight as part of a joint and multinational force. The United States cannot achieve its
  security interests without the cooperation of treaty allies, partner nations, and other unified action partners.
  Helping partner nations build, rebuild, or maintain their national security institutions is a critical step in
  maintaining regional stability, and it is ultimately less expensive than requiring U.S. forces to do so.
  Additionally, by maintaining partner-nation security institutions, the Army helps add to the aggregate force
  that is available to potentially deter adversary forces or counter them if they choose to pursue their goals
  through armed conflict. Forward-stationed U.S. Army forces, by themselves, generally do not enjoy favorable
  combat power ratios with peer adversaries. Allies and other partners provide the bulk of forces initially able
  to conduct operations during armed conflict. This combined force capability enhances deterrence for both
  the partner nation and the United States. (See paragraphs 4-39 through 4-52 for more information on how
  Army forces help build allied and partner capabilities.)
  4-17. Combined training and exercises with partners play a key role in building allied and partner capabilities
  and shaping an operational environment. Such events are the most overt and visible means of demonstrating
  friendly capabilities, interoperability, and will. Exercises also help set the theater. Multinational forces that
  maintain high levels of combat readiness provide the credibility essential to assure partners and deter
  adversaries. Combined exercises build relationships and mutual respect among allies and other multinational
  partners, identify systems and processes to employ partner capabilities effectively, and reveal shortfalls to be
  improved upon. Training exercises occur at all echelons of command, from tactical units to large, combined
  task forces. The application of lessons learned during these exercises is key to improving multinational
  interoperability during competition. An example of a failure to prepare for large-scale combat operations
  occurred in the Philippines in 1941.