As someone else mentioned, the South Korean peninsula is defended with much smaller resources because of the geography.
You must realize the U.S. conflict in Southeast Asia was a proxy war. British Minister Anthony Eden did not see much upside to starting another conflict with mainland China, which grew stronger with every year that passed. He was worried about the U.K. lease on Hong Kong island. He knew that Chinese and North Vietnamese leaders despised each other, but formed a temporary alliance because of the mutual interest to eliminate French and American influence locally. The Peking government shipped a steady flow of modern arms and sophisticated equipment to Hanoi and also sent several hundred thousand troops to act as advisors and technical support.
There was a possibility that Thailand might fall to a China-backed Communist regime which would more directly concern border states like British Malaya. Add to the mix, the post-World War II economic conditions in the U.K. and it’s not difficult to understand why Eden and his successors were not eager to atagonize Red China.
Sid Guttridge wrote: ↑23 Apr 2021 11:41Secondly, you write, "North Vietnam did not have an Air Force or Navy that could project power outside of Southeast Asia. The Hanoi regime was never a threat to U.S. national security, its economy, or shipping lanes. " OK. Neither did Laos, Cambodia, Thailand, Burma, Malaysia, Indonesia
If other governments want to waste money on nation-building shenanigans, better them than us. Wagering on South Vietnam was akin to Manchester United hiring a striker who cannot score a goal, then rewarding his ineptitude with 20 years of lucrative contracts.
Not in Vietnam, according to General Matthew Ridgway, U.S. Army Chief of Staff in the 1950s. He lobbied strongly against sending American troops to French Indochina after the Battle of Dien Bien Phu. Ridgway’s warnings proved quite prescient when they were ignored ten years later. He wrote:
“However futile it might have been to stand and fight in that spot, still, the gallantry of the hard-fighting French garrison did capture the imagination of the world. Soon I was deeply concerned to hear individuals of great influence, both in and out of government, raising the cry that now was the time, and here, in Indo-China, was the place to "test the New Look," for us to intervene, to come to the aid of France with arms. At the same time that same old delusive idea was advanced that we could do things the cheap and easy way, by going into Indo-China with air and naval forces alone. To me this had an ominous ring. For I felt sure that if we committed air and naval power to that area, we would have to follow them immediately with ground forces in support.
I also knew that none of those advocating such a step had any accurate idea what such an operation would cost us in blood and money and national effort. I felt that it was essential therefore that all who had any influence in making the decision on this grave matter should be fully aware of all the factors involved.
To provide these facts, I sent out to Indo-China an Army team of experts in every field: engineers, signal and communications specialists, medical officers, and experienced combat leaders who knew how to evaluate terrain in terms of battle tactics. They went out to get the answers to a thousand questions that those who had so blithely recommended that we go to war there had never taken the trouble to ask.
How deep was the water over the bar at Saigon? What were the harbor and dock facilities? Where could we store the tons of supplies we would need to support us there? How good was the road net how could supplies be transported as the fighting forces moved inland, and in what tonnages? What of the climate? The rainfall? What tropical diseases would attack the combat soldier in that jungle land?
Their report was complete. The area, they found, was practically devoid of those facilities which modern forces such as ours find essential to the waging of war. Its telecommunications, highways, railways all the things that make possible the operation of a modern combat force on land were almost non-existent. Its port facilities and airfields were totally inadequate, and to provide the facilities we would need would require a tremendous engineering and logistical effort.
The land was a land of rice paddy and jungle particularly adapted to the guerrilla-type warfare at which the Chinese soldier is a master. This meant that every little detachment, every individual, that tried to move about that country, would have to be protected by riflemen. Every telephone lineman, road repair party every ambulance and every rear-area aid station would have to be under armed guard or they would be shot at around the clock.
If we did go into Indo-China, we would have to win. We would have to go in with a military force adequate in all its branches, and that meant a very strong ground force an Army that could not only stand the normal attrition of battle, but could absorb heavy casualties from the jungle heat, and the rots and fevers which afflict the white man in the tropics. We could not again afford to accept anything short of decisive military victory.
We could have fought in Indo-China. We could have won, if we had been willing to pay the tremendous cost in men and money that such intervention would have required a cost that in my opinion would have eventually been as great as, or greater than, that we paid in Korea. In Korea, we had learned that air and naval power alone cannot win a war and that inadequate ground forces cannot win one either. It was incredible to me that we had forgotten that bitter lesson so soon that we were on the verge of making that same tragic error.
That error, thank God, was not repeated. As soon as the full report was in, I lost no time in having it passed on up the chain of command. It reached President Eisenhower. To a man of his military experience its implications were immediately clear. The idea of intervening was abandoned, and it is my belief that the analysis which the Army made and presented to higher authority played a considerable, perhaps a decisive, part in persuading our government not to embark on that tragic adventure.”
SOLDIER: The Memoirs of Matthew B. Ridgway, 1956.