text: Operations During Competition Below Armed Conflict
  Failure to Prepare for War: Philippines, 1941
  During the summer of 1941 the United States Army took steps to prepare for potential
  armed conflict with Japan. The War Department created the United States Army
  Forces in the Far East (USAFFE) and recalled General Douglas MacArthur to active
  duty to serve as the commanding general. The War Department provided USAFFE
  with the priority for equipment and reinforcements within the Pacific Theater of
  Operations to support General MacArthur’s defensive plans.
  By December 1941, USAFFE had made significant strides, but had not done enough
  to effectively prepare for armed conflict. When Japan’s forces attacked the Philippines
  on 8 December 1941, ten hours after their attack on Pearl Harbor, Hawaii, USAFFE
  was short personnel, supplies, and equipment. Aside from a provisional tank group,
  most forces were ill equipped and possessed obsolete weapons and vehicles. The
  Philippine armed forces, whose readiness was also a USAFFE responsibility, were
  even less prepared than U.S. forces. They lacked modern weapons, effective logistics
  systems, and training. The War Department and USAFFE attempted to make up for
  these shortcomings by distributing supplies from pre-positioned stocks on the islands
  of Corregidor and the Bataan Peninsula to both U.S. and Philippine units stationed
  throughout the archipelago.
  The Far East Air Force was equally unprepared. It lacked early warning systems and
  anti-aircraft artillery. Planned survivability improvements to airfields were incomplete,
  leaving aircraft exposed on flight lines and parking aprons. As a result, the Far East Air
  Force lost over half of its aircraft by the conclusion of the first day of the war, most of
  which were destroyed on the ground.
  Although the U.S. and Philippine forces mounted a fierce resistance for nearly six
  months, Japan eventually isolated the defenders in the Bataan Peninsula and on the
  island of Corregidor with naval and air forces. In the absence of friendly air and naval
  support, the U.S. and Philippine forces were unable to receive reinforcements,
  resupply, or conduct an evacuation. As a result, the U.S. and Philippine forces in the
  Bataan Peninsula fell to Japan’s forces in April 1942, and the remaining forces on
  Corregidor and the surrounding islands surrendered in May 1942.
  INTEROPERABILITY
  4-18. The ability of Army forces to fight as a cohesive whole, integrated with the joint force, allies, and
  partners, is vital to maximizing combat power and creating a deterrent effect in a theater. Interoperability is
  the ability to act together coherently, effectively, and efficiently to achieve tactical, operational, and strategic
  objectives (JP 3-0). An Army formation that is interoperable with joint and multinational partners is
  substantially more capable than one that is not. Interoperability with any unified action partner is essential to
  effective operations. Interoperability standards and procedures must be trained, tested, and refined during
  competition; it is too late to seek interoperability once a crisis or armed conflict begins.
  4-19. Interoperability starts with mutual understanding across echelons throughout a multinational force.
  Effective interoperability includes understanding technical challenges and developing methods to bridge
  gaps, understanding the tactical capabilities of each member in the multinational force, and integrating
  partners into a unified operational approach. During competition, the theater army or a delegated command
  is responsible for building the infrastructure that enables this. Communication is primarily achieved through
  liaison teams, understanding staff processes, and ensuring adequate access to partner nation command and
  control (C2) systems (within the limits of national caveats). Understanding foundational interoperability
  requirements like NATO doctrine; American, British, Canadian, Australian, and New Zealand (known as
  ABCANZ) Armies Program interoperability standards; and Combined Forces Command (in the Republic of