"'In this treacherous world Nothing is the truth nor a lie. Everything depends on the color Of the crystal through which one sees it'” ― Pedro Calderón de la Barca.
In this particular case the "crystal" is radar blips, sonar sounds, phosphorescent torpedo traces, etc.
The Gulf of Tonkin Incident. From 1964. American warships on the high seas attacked by motor torpedo boats of the North Vietnamese Navy. Attacks, one absolutely confirmed during hours of daylight, a second alleged during hours of darkness, the U.S. Congress in the aftermath authorizing President Johnson to use force as deemed necessary to protect American interests in SE Asia. FOR ALL THAT MEANT IN THE YEARS TO FOLLOW - - THE SECOND INDO-CHINA WAR!!
IT IS INDISPUTABLE THAT AMERICAN WARSHIPS DURING HOURS OF DAYLIGHT DID SUSTAIN ATTACK BY NORTH VIETNAMESE TORPEDO BOATS! THAT IS NOT IN DISPUTE!
What is in dispute and to a degree was in dispute at the time  was the second attack, occurring during hours of darkness as alleged.
Controversial to an extent at the time, in hindsight attacks THOUGHT TO HAVE OCCURRED even if based upon specious evidence!
Specious evidence such as:
1. The phosphorescent wakes of torpedoes were seen, or were they NOT seen!
2. Unmistakable radar blips indicating the American warships were under attack or radar blips were seen and misinterpreted!
3. Sonar operators reported hearing torpedoes in the water or did NOT hear torpedoes in the water.
Those naval officers and crew of the USS Maddox and the USS Turner Joy obviously on edge and jittery, knowing full well that just some hours previously they HAD BEEN in the cross hairs of North Vietnamese torpedo attack.
The further nighttime attack, alleged, is best understood in what is commonly described as the "Fog of War", those uncertainties under which the military man in a chaotic situation perceives and interprets his surroundings:
"The fog of war is a term used to describe the uncertainty in situation awareness experienced by participants in military operations. The term seeks to capture the uncertainty regarding own capability, adversary capability, and adversary intent during an engagement, operation, or campaign."
"War is an area of uncertainty; three quarters of the things on which all action in War is based on are lying in a fog of uncertainty to a greater or lesser extent. The first thing (needed) here is a fine, piercing mind, to feel the truth with the measure of its judgment." - - Clausewitz.
"The great uncertainty of all data in war is a peculiar difficulty, because all action must, to a certain extent, be planned in a mere twilight, which in addition not infrequently — like the effect of a fog or moonlight — gives to things exaggerated dimensions and unnatural appearance." - - Clausewitz
The perception which became reality based upon evidence seen with hindsight as spurious and probably misleading was that the Maddox and Turner Joy HAD BEEN ATTACKED FOR A SECOND TIME, DURING HOURS OF DARKNESS, CONTACT WITH THE ADVERSARY INFERRED BUT NOT ABSOLUTELY 100 % VERIFIED!!
In this case perception became reality and was acted upon, with the results speaking for themselves
* The National Command Authority [NCA] to include President Johnson at that exact moment given the evidence as was presented to them were not guilty of fabrication or prevarication? Did honestly believe that a second attack during hours of darkness did indeed occur.
* The consequences of these errant reports and judgement were most extreme? The entire episode of increased American escalation allowing combat forces to engage in an offensive manner and not merely defensive lead to circumstances that are being debated even forty or more years later!!
* I would be lacking and remiss if not to mention that prior to the daylight attack both American warships had been engaged in a combat support mission in support of a South Vietnamese raid on North Vietnamese territory and could have been deemed as justifiable targets for attack!!