How did the Gulf of Tonkin Resolution impact the Vietnam War?

increased involvement because it allowed the US President to make military actions, like increase troops, without formal declaration of war

all of these

the Gulf of Tonkin Resolution drastically shortened the Vietnam War

the total number of US troops in Vietnam went down because Congress now had to authorize sending more troops, and Congress was hesitant to send more troops

Increased involvement because it allowed the US President to make military actions, like increase troops, without formal declaration of war.

The Gulf of Tonkin Resolution, passed by Congress in August, 1964, after alleged attacks on two US naval ships in the Gulf of Tonkin. The key wording in the resolution said:

R esolved by the Senate and House of Representatives of the United States of America in Congress assembled, t hat the Congress approves and supports the determination of the President, as Commander in Chief, to take all necessary measures to repel any armed attack against the forces of the United States and to prevent further aggression.

That resolution served as a blank check for President Johnson to send troops to whatever extent he deemed necessary in pursuance of the war. Between 1964 and the end of Johnson's presidency in 1969, US troop levels in Vietnam increased from around 20,000 to over 500,000.