The Americans got involved in the Vietnam War because they did not want another Communist party to hold Vietnam as its captive. Vietnam along with other South East Asian countries have undergone communist rule from China and France, Americans did not want to see that happening again, that's why they aided or supported the Vietnamese from the war that they were waging against communist countries.
Well this was i guess you could say part of the US involvement in the cold war. They supported south Vietnam because they didn't want communism from china and Russia spreading their. So when the two together planned an invasion of south Vietnam they announced their involvement to help try and stop it. Also they got involved because they threatened that since they were an ally of ours any attempt to gain land would be met with hostile reinforcement of the area. They were losing heavy casualties and american involvement in the war was not widely supported by the public. Fighting in Vietnam was life and death. Many attacks were deadly as heavy losses on both sides tolled up. We withdrew because most of american citizens hated the war and didn't support it. So the president facing battles on the home front and facing battles in Vietnam decided to withdraw to appease the public. The effects of the withdrawal were that many young soldiers got to see their families again. Many families also were happy as with less money being funneled into the war many new buildings and public services were built. A bad part of the war was after the US left the south was invaded and they ended up with a communist government. Another effect was that the Us pride was hurt and some countries viewed us as weak.
The transfer of power from the central government to state or local government is called "devolution," since this would be the opposite of a smaller power "evolving" into a larger one.
