The correct answer to this open question is the following.
Unfortunately, you forgot to attach the statement of Robert F.Kennedy, the excerpt, or a link to it. We do not what it is.
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According to Robert F. Kennedy, the lesson that needed to be learned was that the ultimate victory in Vietnam War was going to be very difficult to obtain. This created some turmoil in American politics in the Lyndon B. Johnson administration to the degree that Kennedy proposed a plan to end the war.
The plan included three unnegotiable points that were: no more bombing of North Vietnam, and the gradual withdrawal of the US soldiers and North Vietnam soldiers from South Vietnam.
The plan was not accepted by Dean Rusk, who was the Secretary of Defense.
