do you mean what caused us entry into world war one? if so then the sinking of the USS Lusitania by German u-boats was what caused American entry into the war
The draft.
The fear of being invaded was not a justification for the increase in US involvement in Vietnam. The US withdrew from Vietnam in 1975.
Militarism, the other three causes for US entry into the war are imperialism nationalism and alliances.
After the US withdrew from Vietnam the Vietcong came into power. South Vietnam fell under communist rule by the Vietcong.
US assistance to France was the precursor and the introduction of Army advisors was the actual point of US entry into the Vietnam War.
The US got involved in the Vietnam was because they were trying to sweep out communism across the globe. In the war, the US supported South Vietnam because they were fighting against communist North Vietnam.
France was the primary European nation involved with Indo-China prior to the US's entry into Vietnam.
You get to pick. US military men arrived in 1955 & they left forever in 1975.
The policy at the time was the Domino Theory, so in protection and practice of the theory, yes it was justified.
do you mean what caused us entry into world war one? if so then the sinking of the USS Lusitania by German u-boats was what caused American entry into the war
Myanmar passport holders are required visa for entering Vietnam.
the attack of two U.S. destroyers by the North Vietnamese. Gradpoint
the attack of two U.S. destroyers by the North Vietnamese. Gradpoint
The US never invaded Vietnam.
The official beginning of the conventional war (infantry, tanks, jets, etc.) and war between America and North Vietnam were the Tonkin Gulf naval battles (called incidents) in August 1964.
Vietnam was part of the COLD WAR. It was fought to stop the spread of communism.