The reasons why the Vietnam War lasted so long is a very controversial subject among Americans. There is no simple answer to as why the war lasted so long. Many factors have to be considered when analyzing the war. The first factor that has to be considered is whether or not the U.S. really belonged in the Vietnam War in the first place. The initial reason that the U.S. became involved in Vietnam was because they thought that North Vietnam was going to Russia and China, which were communist countries, for support. Because of the containme ....