Organized as a unit less than four months, the brigade left behind it a reputation for mobility, effectiveness, and rapid deployment in the face of national emergency. Although Marine air and ground forces had operated together since 1919 in Haiti, formation of the 1st Provisional Marine Brigade “marked the first time that the air and ground elements, task organized under a single commander, had engaged in combat.”[693]
[693] Ibid. Even though Marine air and ground forces had on occasion operated jointly ever since the 1920s, air support in the early days was considered a subsidiary rather than integral part of the team. The doctrine of Marine close air support was formulated in WW II but not fully employed before the end of hostilities.
In the brilliant Inchon landing of 15 September 1950, Major General Oliver P. Smith’s 1st Division Marines led the X Corps attack in the first major counterstroke by United Nations forces on Communist-held territory. This maneuver was closely timed against enormous odds of personnel, logistics, and hydrography (tidal fluctuations of 31 feet) which made 15 September the only suitable assault date until mid-October. When outlined in earlier planning sessions by General MacArthur, the mammoth difficulties of the operation had been so unsettling that the designated Attack Force Commander for the landing, Rear Admiral James H. Doyle, expressed the view that “the best I can say is that Inchon is not impossible.”[694]
[694] Quoted in USMC Ops Korea, v. II, p. 46. Admiral Doyle was Commander of Amphibious Forces for the Pacific Fleet.
Despite all the difficulties, the landing at Inchon and recapture of Seoul, the South Korean Capital, and its adjacent Kimpo airfield by the Marines was a stunning tactical blow by the UNC that broke the backbone of the North Korean People’s Army 1950 offensive. The 1st Marine Division, in its successfully executed amphibious landing, had offered UNC forces an opportunity to defeat the enemy decisively before a Siberian-like Korean winter set in. Accomplished under the most adverse weather and geographic conditions, the assault proved anew the decisive power of amphibious forces employed at a critical time and place. This capability and readiness of the Marine Corps had totally reversed the military situation, and a battered enemy was on the run. The subsequent routing of the NKPA divisions in the Inchon-Seoul campaign by X Corps and the Eighth U.S. Army forces would have led to an early UN victory had not the Chinese Communists intervened to support their Korean counterparts. The operation had validated Far East Commander General MacArthur’s early premise that:
... air and naval action alone could not be decisive, and that nothing short of the intervention of U.S. ground forces could give any assurance of stopping the Communists and of later regaining the lost ground.[695]
[695] Ibid., p. 3.
The Inchon operation, moreover, had been planned in record time—approximately 20 days. This was one of the shortest periods ever allotted to a major amphibious assault, involving the planning, assembly of shipping, and mounting out of a combined force of 29,000 Marines and support personnel.
With the Inchon-Seoul operation ended, the 1st Marine Division (including the 7th Marines which had reached Inchon in time for the liberation of Seoul) reembarked on 12 October for deployment to the east coast of Korea. A new military operation was envisioned north of the 38th Parallel against Pyongyang, the North Korean Capital. As part of the drive, X Corps was to make an amphibious envelopment on the east coast, in the area of the enemy-held port of Wonsan. From here X Corps would advance westward toward Pyongyang, to link up with Eighth Army troops and trap NKPA forces withdrawing from the south.
While the Marines were en route to the objective, word was received that ROK troops had overrun Wonsan and were pushing north. The revised X Corps plan of operation called for a three-pronged attack towards the Yalu. The Marine division would advance on the left, the U.S. Army 7th Division in the center, and 1st ROK Division on the right flank. This drive to the north and subsequent action at the Chosin Reservoir would rank as one of the most rigorous campaigns in the entire history of the Marine Corps.