Most informed Americans know now that the United States drastically escalated its intervention in the Vietnamese civil war under the pretext of North Vietnamese attacks on its warships collecting intelligence off the coast in the Gulf of Tonkin. It is doubtful the reported attack actually took place. Nevertheless President Johnson used the claimed attacks to pressure Congress into passing a war resolution authorizing the US military to expand beyond its advisory role into war fighting. What is less known is that Johnson used an almost identical "false flag" subterfuge to attempt justifying US intervention in the 1967 Six Day War between Israel and Egypt and her Arab allies. Fortunately, the Israeli attacks on the USS Liberty, a US signals intelligence ship off the coast of Sinai, were witnessed by a Soviet vessel which destroyed any plausible attribution of the attack to Egypt.
The eyewitness account of an officer serving on the Liberty can be viewed here.