* * *
After his arduous trip to South Korea MacArthur returned to his home in Tokyo for a good night's sleep. While he slept, the JCS, now receiving a continuous stream of reports from various sources in Korea and Japan, began to realize that with the ROK Army disintegrating, it was doubtful that American air and sea power alone could save South Korea. During that day - June 29, [3-11AM] Washington time - the full JCS concluded, reluctantly, that if South Korea were to be saved, the use of some American ground forces could probably not be avoided much longer.[3-43]
Two purely military considerations pushed the chiefs closer to committing limited American ground forces that day.
The first was the need to ensure the safety of the airfield at Pusan. It and the field in Suwŏn (which might be lost at any hour) were the only two air installations in South Korea capable of handling the big four engine C54 Air Force transports which were now being employed to bring in emergency supplies of ammunition to the ROKs and to evacuate American stragglers.
The second consideration was the need to ensure the safety of the South Korean seaports of Pusan and Chinhae (twenty miles east of Pusan), which the American Navy was using as unloading points for ammo and supplies.[3-44]