If the US is capable of anything, it is the author of an imperfect future in which the best of intentions always seems to yield bad fruit. In order to project the potential consequences of what the American defeat in Afghanistan will look like, it is instructive to reflect on the US involvement in Vietnam. History certainly does not repeat itself but it certainly rhymes over time.
Could the United States have secured a free South Vietnam? Did the United States have all the necessary political and military capital to prosecute a major land conflict in Southeast Asia and create a self-sustaining nation neutral or beneficial to American security interests in the area? I would suggest the United States did not and will not for the foreseeable future have the capability to answer the latter in the affirmative and therefore the answer to the former question is a definitive no. America, despite it formidable might with no technological peer will lose.
The Vietminh in Saigon accidentally gunned down LTC A. Peter Dewey of the office of Strategic Services (OSS) in September 1945. What is important to know from this solitary death is that Ho Chi Minh and his Vietminh regretted this and did what they could to atone. Uncle Ho had his finger on the international pulse both within the ranks of the small and large C comintern and the importance of crafting and staying on message first and consistently. Dewey would not be the first American to fall there. He would be followed by tens of thousands of other dead and hundreds of thousands of physically and mentally injured Americans during the long American night in Vietnam that would emerge within a generation.
The North Vietnamese and its attendant unconventional legions were tough, resourceful, well-trained and consistently had their eyes on the end-state Ho Chi Minh sought – a unified ideological peninsula with like-minded neighbors that suborned all colonial influence to self-determination.