war in Vietnam- it is good? War in Vietnam was the longest conflict in the postwar history. Was consisted with two conflicts. First war began at the end of 1946 and United States supported France. Vietnam became the key player in the cold war and it was a barrier before the expansion of the communist block. The result was formulated the domino theory by the President Eisenhower. J. F. Kennedy introduced American troops to Vietnam but his successor Johnson began the escalation of the war. Incidents in the Tonkin Gulf led the United States to engage in a conflict between the two Vietnamese countries. The year 1965 is recognized in American historiography for starting an open war in Vietnam. Began in this year the operation “Rolling Thunder”. War aroused antipathy among politicians and society. But the Tet Offensive became a turning point in the war, the symbol of failure and helplessness of United States troops. In 1968 Nixon won the election thanks to the announcement of the withdrawal of United States troops. The period between 1969 and 1973 was crucial for both: the United States and Vietnam. American foreign policy shaped the Nixon doctrine and strategy of “vietnamization”. On the other hand negotiations to achieve peace with honor were led by Kissinger. It finished with the signing of the Paris Treaties and ended the United direct involvement in the Vietnam conflict. Discrepancies presidents and presidential administration on policy towards Vietnam contributed to the political and later military defeat of the United States. Thousands of victims, wounded, missing, damage to the prestige of the United States in the international arena, the protests, the enormous costs - these are the effects of United States involvement in the Vietnam War. United States have had political, military, intellectual, and moral disaster - and the domino theory has not been fulfilled. However, President Nixon's slogan is still actual "never more Vietnams".