Conflict in South Vietnam began around 1959 when Prime Minister Ngo Dinh Diem outlawed political violence against the southern Vietnamese regime. The US began providing military assistance to the southern Vietnamese as it was concerned about the spread of communism from the north. Diem was killed in a coup in 1963 and the new US president Lyndon B. Johnson began to push for increased US involvement in the country to tackle the Viet Cong communist insurgency, which was estimated to have around 100,000 combatants by the end of 1964. The US soon committed itself to a full on ground war, deploying many hundreds of thousands of troops, but its efforts proved largely ineffective against the guerrilla tactics of the Viet Cong, which were suited to the region’s dense jungle. Public outrage grew at the high number of US deaths and the Americans gradually withdrew following a peace deal with North Vietnam in 1973. The north then invaded the south in 1975.
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