With a class rank at Annapolis of 894 out of 899, it's a good bet he didn't show up in Viet Nam with a lot of brain to start with.
John McCain got INTO the Naval Academy in the first place, because he was a “heritage” applicant. His father and grandfather were both flag rank officers, and if John had not been such a squirrel, BEFORE he was captured by the VC, he probably stood in line to become a flag rank officer himself.
But John Sidney McCain III (the full name of the GOP Presidential campaign of 2008) was something of a misfit, with few distinguishing characteristics as an officer, and had he not been the son and grandson of admiral officers held in high regard by the Navy, he would have been drummed out long before he was captured by the VC following what had been a record of poor regard for the equipment for which he was given responsibility, being involved in several crashes and a near-death experience on the USS Forrestal. To be honest, McCain was only there in the line of a very serious fire involving another plane first, but which resulted in the deaths and injury of a large number of sailors and serious disabling of the aircraft carrier, subsequent to which time he was transferred to another carrier, the USS Oriskany.
There is an old saying about there being old pilots, and there are bold pilots, but there are no old, bold pilots.
McCain’s judgment was high-risk at best, as he had a tendency to ignore training manuals and schedules, and would push the envelope more than a little on occasion, including the day he was shot down over North Viet Nam on October 26, 1967. On a raid where he was coming in a little closer and hotter, a SAM missile took off the wing of his
craft, and his problems only got worse from then on. Suffering two broken arms and a broken leg after ejecting, he came down in a lake, where he was fished out of the water by civilian Vietnamese, who proceeded to brutalize him and kick him about. And this was even before the Viet Cong got to him.
McCain, to his everlasting credit, probably suffered an uncommon degree of abuse and privation that would have killed anybody with a lesser will to live, and equaled or exceeded what most other prisoners of the Viet Cong endured. That he finally gave up some information beyond name, rank, serial number and date of birth, none of it was to prove to be of any real use to the Viet Cong.