In World War II, the United States narrowly escaped a crushing defeat because of neglect of a major principle of war: the principle of cooperation.

Until the invasion of the Philippines on October 20–23, 1944, we had fought two separate wars in the Pacific: the advance through the Central Pacific and the Gilbert, Marshall, and Mariana Islands, and the war in the Southwest Pacific via the Solomons and New Guinea. The forces of the former were commanded by Admiral Chester Nimitz in Hawaii; the latter by General Douglas MacArthur in Australia. When these advances met in the Philippines, the two leaders had no superior short of the commander in chief, the president of the United States.

The invasion was the responsibility of General MacArthur, with Central Pacific Forces filling a supporting role. The Seventh Fleet under the command of Vice Admiral Kincaid was given to General MacArthur for the invasion and included units of escort carriers and old battleships, some of which had been raised from Pearl Harbor. The ammunition of these units was non-armor-piercing, high explosives, as they were for support of the troops ashore and not for an engagement at sea. Protecting the invasion from attack by sea was the Third Fleet, commanded by Admiral Halsey under Admiral Nimitz. The main striking force consisted of four carrier air groups each with four fast-attack carriers and a surface striking force of fast new battleships.

The Japanese sent a two-pronged surface attack against the invasion fleet in Leyte Gulf and a decoy carrier group from Japan into the Philippine Sea. The old battleships under Rear Admiral Oldendorf sank all but one cruiser in Surigao Strait, which took care of the southern prong. The fast-attack carriers turned back the northern prong in the Sibuyan sea and then proceeded after the decoy group away from the invasion fleet.

Because of poor communication between the commanders of the Third and Seventh Fleets, Admiral Kincaid thought that Admiral Halsey had detached his surface striking group of seven fast battleships to cover the northern prong of the Japanese surface force at San Bernardino Straits. In reality, Admiral Halsey took the battleships with him after the decoy air group. He had not let the commander in chief, Pacific, or commander, Seventh Fleet, know of his decision.

The Japanese northern arm returned to the attack, coming through San Bernardino Straits with four battleships and ten heavy cruisers. No one was there to meet them. They caught our escort carriers in Leyte Gulf. After sinking the Gambier Bay, for some unknown reason the Japanese admiral retreated. His only opposition consisted of torpedo attacks and smoke from destroyers and destroyer escorts. Our forces had intelligence of the enemy. We had an overwhelming superiority in surface and air power. But we did not obtain a decisive victory because of poor communication between cooperating forces. If it had not been for the decision of the Japanese admiral to retire, we might have suffered a decisive defeat.

When we fail to uphold the principle of cooperation, we cannot count on the enemy making mistakes or poor decisions, nor can we bank on scaring him with smoke and mock torpedo runs.

We must determine to have an overwhelming superiority to meet the enemy in a decisive battle at the right time, which cannot be achieved without cooperation. This cooperation is dependent upon two prerequisites:

1. Cooperating forces are allies, not belligerents.

2. The cooperating forces come under one commander.

Cooperation with an enemy is treason. Failure to cooperate with an ally is a violation of an essential principle of war and a gross error.

Unity of command is necessary for cooperation. The closer the commander is to the cooperating forces, the closer the cooperation. The farther removed the unity of command, the weaker the cooperation. In the invasion of the Philippines the supreme commander, the president of the United States, was very distant. Admiral Nimitz had a unified command; so did General MacArthur. But this was a meeting of two distinct commands—they had no common superior close enough to the situation to provide good cooperation.

*Excerpted from Principles of War. To purchase, visit