In spite of being little more than a tool in the hands of the U.S., Diem was nonetheless a very capable minion. With the purpose of destabilizing Diem's power, Kennedy "recalled the CIA station chief in Saigon, John Richardson, who was known to be friendly with Ngo Dinh Nhu" and "cut off the funds to support some Special Forces under Nhu's Control" (Moss 109). Predictably, the coup overthrowing and murdering Diem did not last for long and conditions became unfavorable for South Vietnam. Diem was followed by several leaders who appeared to be supportive toward the U.S. And against communist, but none matched the former leader in reputation and in managing abilities. When hearing that the Americans supported the coup, the North Vietnamese realized the mistake their enemies did and embarked on a mission to take over South Vietnam and defeat any troops they encountered in their way, with no regard to their ethnicity.

The coup against Diem was expected to be a simple event in the course...

Diem's excessive living style and the fact that he imposed absurd laws only managed to get the public even more infuriated concerning his leadership. One can actually claim that the success of the North Vietnamese was largely owed to Diem's demise from the ruling of South Vietnam. Also, with Diem dead, the Americans were left with little to no chances to stop the North Vietnamese from conquering their southern counterparts.
The Americans overestimated themselves and "failed to understand the extent to which they were perceived as outsiders meddling in the internal affairs of Vietnamese people" (Moss 115). Diem's execution and the fact that South Vietnam came to be ruled by an unstable government is certainly one of the main reasons for which the U.S. lost the Vietnam War.

Works cited:

1. Moss, G. (2009). "Vietnam: An American Ordeal (6th Edition)." Prentice Hall.