ORIGINAL: ThunderLizard2
Marines again proved their worth (if that was even required) in Korea at the Pusan perimeter where the 5th Marines held the line against fierce attacks.
It does seem incredible after the feats of valor the Marines performed in WWII that it would ever be an issue, but yeah, the future of the Corps was in jeopardy even then. They had to fight for survival in the Senate in 1947. The Army brass really resented the Marines’ intrusion into the Army’s customary land-warfare sphere. With the coming of peace and the succession to the presidency of Harry Truman, who harbored anti-Navy and anti-Marine Corps biases, force unification was pursued in earnest. General George C. Marshall, was overheard muttering that the Corps should be kept “very small” and vowing that he would “see that the Marines never win another war.” Jealousy over good Marine press was definitely a factor.
Anyway, Eisenhower, Marshall, Truman, and the rest soon had to eat North Korean crow.
Like you said, the Korean war started and it was a conventional war. The Marines saved Pusan and Inchon became a classic amphibious operation by the First Marine Division.