What event caused the stepped-up U.S. involvement in the Vietnam War as noted in the nonfiction book, Most Dangerous?

The Gulf of Tonkin incident caused the stepped-up U.S. involvement in the Vietnam War. Sadly, it was probably predicated on false information. A cable from an officer on the war front was received at the Pentagon claiming that U.S. naval ships had been torpedoed by the North Vietnamese in the Tonkin Bay. President Johnson met with key members of the cabinet about the incident. Johnson approved the bombing of key targets pointed out to him on a reconnaissance photos.