The Gulf of Tonkin incident, which happened in August 1964, marked a major escalation of the Vietnam War. Congress passed a resolution known as the Gulf of Tonkin resolution, which gave the president the authority to send American troops to Vietnam. From this point on, President Lyndon Johnson sent hundreds of thousands of American soldiers to fight in Vietnam and keep North Vietnam from conquering South Vietnam. Until this point, America's role in Vietnam had been advisory only.
