When Nixon came to power, the issue of American troops' withdrawal was not a question, yet it was diplomatically challenging to leave Vietnam in a proper ideological way. Because it was important to give an opportunity to South Vietnam establish a democratic state after American leave, the negotiation were led in that direction. The lesson from negotiation's success, which was earlier unachievable, lies in flexibility and assertiveness that administration had. American administration stopped being a hostage of both enemies and allies, and worked out its own position.
As for presidential leadership, there were several US leaders in a row who participated in the conflict. The more publicity and involvement the war got, the weightier was Vietnamese card in US internal and external politics. Eisenhower, Johnson, Kennedy and Nixon had to deal with the issue in their own way. Presidents' personal position affected the flow of the conflict significantly: while Kennedy was against sending troops to Vietnam, it was during Johnson's reign that the war escalated. Even though external factors influenced their decisions, the lesson is that the political will of a leader can determine events.
Culturally and socially, it is obvious that the beginning of the war was initially determined by the decay of colonialism and imperialism. Because France and its allies would refuse to give independence to their colony, the war escalated. The politicians did not realize that the growth of national consciousness would mean hard oppression, and totally different mentality would make the task of managing the local government a challenge.
In conclusion, it should be noted that studying past events enables to understand that history woks in cycles, and that there are always analogies for current events. It is worth looking back at the past to learn lessons in order to take more reasonable decisions nowadays.