Generations of US high school students have been taught that the Gulf of Tonkin Incident was the main reason the US entered the Vietnam War. Supposedly, US warships had been attacked "unprovoked" twice by the North Vietnamese navy. In truth, those US warships were giving assistance to the South Vietnamese, so they were not exactly neutral. As for the second attack, well, turns out it never actually happened. This isn't from some goofball conspiracy theorist- Robert McNamara (Secretary of Defense at the time) and James Stockdale (who was flying over the place when the second attack allegedly occurred) have both denied it.
"In 1995, retired Vietnamese Defense Minister Vo Nguyen Giap, meeting with former Secretary of Defense McNamara, categorically denied that Vietnamese gunboats had attacked American destroyers on 4 August, while admitting to the attack on 2 August. A taped conversation of a meeting several weeks after passage of the Gulf of Tonkin Resolution was released in 2001, revealing that McNamara expressed doubts to President Johnson that the attack had even occurred."
"Squadron commander James Stockdale was one of the U.S. pilots flying overhead during the second alleged attack. Stockdale wrote in his 1984 book Love and War: "[I] had the best seat in the house to watch that event, and our destroyers were just shooting at phantom targets—there were no PT boats there… There was nothing there but black water and American fire power." Stockdale said his superiors ordered him to keep quiet about this. After he was captured, this knowledge became a heavy burden. He later said he was concerned that his captors would eventually force him to reveal what he knew about the second incident."
source
So, what we have is a war based on a flimsy pretext. Now when has that ever happened?
"In 1995, retired Vietnamese Defense Minister Vo Nguyen Giap, meeting with former Secretary of Defense McNamara, categorically denied that Vietnamese gunboats had attacked American destroyers on 4 August, while admitting to the attack on 2 August. A taped conversation of a meeting several weeks after passage of the Gulf of Tonkin Resolution was released in 2001, revealing that McNamara expressed doubts to President Johnson that the attack had even occurred."
"Squadron commander James Stockdale was one of the U.S. pilots flying overhead during the second alleged attack. Stockdale wrote in his 1984 book Love and War: "[I] had the best seat in the house to watch that event, and our destroyers were just shooting at phantom targets—there were no PT boats there… There was nothing there but black water and American fire power." Stockdale said his superiors ordered him to keep quiet about this. After he was captured, this knowledge became a heavy burden. He later said he was concerned that his captors would eventually force him to reveal what he knew about the second incident."
source
So, what we have is a war based on a flimsy pretext. Now when has that ever happened?