Throughout his Senate career, [John] McCain has quietly sponsored and pushed into federal law a set of prohibitions that keep the most revealing information about these men buried as classified documents. Thus the war hero who people would logically imagine as a determined crusader for the interests of POWs and their families became instead the strange champion of hiding the evidence and closing the books.I've not delved into the POW/MIA issue but one of the indicators of official allergy to the truth about this issue that I ran across in the 1980s or early '90s was an account in the Washington Times of a POW/MIA office the U.S. maintained in Thailand. Apparently the office was to be closed down. However, the really strange thing was that the officer in charge, a brigadier general, had been personally involved in destroying the paper records of that office. As in "hands on" involved. Somebody absolutely, positively wanted those records gone for a general officer personally to have been involved in their destruction. And what about those records of this ultra sensitive subject required their destruction rather than removal to some archive back home? Heck, was it even legal under any version of the Federal Public Records Act that today is making things oh-so-minutely uncomfortable for Mrs. Clinton?
The sum of the secrets McCain has sought to hide is not small. There exists a telling mass of official documents, radio intercepts, witness depositions, satellite photos of rescue symbols that pilots were trained to use, electronic messages from the ground containing the individual code numbers given to airmen, a rescue mission by a special forces unit that was aborted twice by Washington—and even sworn testimony by two Defense secretaries that “men were left behind.” This imposing body of evidence suggests that a large number—the documents indicate probably hundreds—of the U.S. prisoners held by Vietnam were not returned when the peace treaty was signed in January 1973 and Hanoi released 591 men, among them Navy combat pilot John S. McCain.
It's been a long time since I read the story but I'm sure about the nature of the office, the involvement of that officer, and the place that the story was reported.
dropped down the memory hole. See also this article about American Korean War POWs who disappeared into the Soviet Union. It cites Laurence Jolidon, author of Last Seen Alive for the proposition "that the government of the United States has not aggressively and completely investigated this issue [U.S. servicemen in Soviet hands] but has allowed it to fade quietly from public view in order to advance other foreign-relations objectives."
Those POW/MIA flags need to be flown to honor the memory of those abandoned men as well as to remind us of the perfidy of our own government in abandoning them.
Whatever the issue – POWs, open borders, amnesty, free trade, globalization, spending, or the destruction of the Constitution – is there any doubt that our national government does NOT care about the American people?
 "McCain and the POW Cover-Up. The “war hero” candidate buried information about POWs left behind in Vietnam." By Sydney Schanberg, The American Conservative, 7/1/2015.