What happened as a result of the Gulf of Tonkin incident in which U.S. and North Vietnamese navy ships fired at each other? A) Johnson decided to bring American troops home. B) The United States declared war on North Vietnam. C) Several American aircraft carriers went into the area. D) President Johnson escalated the fighting in Vietnam.

What this question is really asking

You are connecting an event, the Gulf of Tonkin incident (1964), to its immediate political and military consequence for the United States in the Vietnam War.

What followed the incident: the Gulf of Tonkin Resolution

After reports that U. S. and North Vietnamese ships had exchanged fire, President Lyndon B. Johnson asked Congress for authority to respond. Congress passed the Gulf of Tonkin Resolution in August 1964.

This resolution did not declare war, but it authorized the president to take "all necessary measures" to repel attacks and prevent further aggression in Southeast Asia.

Why D is correct

Because the resolution expanded Johnson’s power to use force, it became the legal and political basis for escalating U. S. involvement, including increased bombing and the later buildup of U. S. ground troops.

Why the other choices are wrong

• A) Wrong, Johnson did not decide to bring troops home; U. S. involvement grew.
• B) Wrong, there was no formal declaration of war on North Vietnam.
• C) Not the main historical result emphasized in textbooks, the key consequence was the policy shift toward escalation backed by congressional authorization.