Writing a Book? Run It Past the Pentagon First.

[Greenday]

Wait, uh... Killing Osama was a gift? Or... I'm confused, what's a gift here?

A framed flag signed by the Seals who were on the raid.

[wolfie]

There are two main issues here:

First, for people in a specialized field, they're surrounded by information/skills specific to that field. It doesn't take much isolation within the community of people in that field to fall into the trap of "of course everyone knows this" (WTF? What do you mean you can't shift an unsynchronized 13-speed manual transmission? How can you NOT know the "alt-numberpad" workaround for the broken keyboard in the driver's room?). Part of the "run this past the brass before publication" is to catch secret information (tactics would be included here - there's only a limited number of ways of doing something, and revealing the way that works best allows the opposition to plan against it) that the author, immersed in the specialist culture, has come to see as common knowledge and therefore no more sensitive to talk about than "the sun rises in the east" (mildly related - a few months ago there was an editorial cartoon where one cop said to another "They're discontinuing the Crown Victoria? Everybody I know drives one!").

Second, and applying to why WW2-era information still can't be released, is that "obsolescent" information may indirectly point to something that's still sensitive. There's the issue of tactics I mentioned earlier, and something I saw in a Tom Clancy novel (quite a while ago, and can't recall which one). I'll summarize it as follows:

The 20 year old (but still classified) file deals with the actions of agent "apple". He's dead now (heart attack), but he recruited agent "pear" who's still active. If the opposition knew that "apple" was an agent, by following up on his associates they might find out about "pear".

[Silverharp]

Sorry about your luck, Matt Bissonnette, but you made promises and oaths not to talk about what the hell you do. One sure as hell does not go and write a book, “forget” to submit it for approval to the DoD and have it published. He has very possibly put other Seal members and missions in danger from the information he’s let out in this book. And before someone points out that he used pseudonym that got leaked. It doesn’t much matter, he still brook his promise to keep his mouth shut.

And teh fact that he had a lawyer on standby before the book hit the shelves says that he knew full well that what he was doing was wrong.