You'll need to choose which thesis to argue. I'll provide you with some of the background info and thoughts.
The incident in the Gulf of Tonkin involved an attack and an alleged attack on US destroyers by North Vietnamese forces in August, 1964. On August 2, the USS Maddox was pursued by North Vietnamese torpedo boats. The Maddox fired warning shots, and the North Vietnamese then attacked with torpedoes and machine gun fire. The US suffered only minor and no casualties; the North Vietnamese boats were damaged and they suffered several casualties. On August 4, there was a report of a second Tonkin Gulf incident was alleged, but this later was revealed as a false report. Nevertheless, the American public was told of two attacks and the incidents were used to get Congress to pass the Tonkin Gulf resolution, which gave the President open-ended powers to deploy troops in the military effort in Vietnam.
The resolution had significant consequences for the Vietnam War and beyond that time. In regard to the Vietnam War, it provided the justification for the president, Lyndon Johnson, to escalate US involvement in the war and magnify the number of US troops there by hundreds of thousands. In US foreign policy in general, it represented an increase of the power of the Commander in Chief (the president) to deploy troops without getting formal approval in advance from Congress.
So for your thesis, you'll need to decide if you believe Congress should have retained more direct authority over the US of American forces in times of conflict, or if you support the idea of the President having greater ability to command the military's deployment on an as-needed basis. Response time is more agile and quick in the hands of the President, but there's less check and balance than having matters vetted through Congress before committing to US action.
