Peter G,

The following is just “knuckleheaded speculation” but I guess that the answer to your question can, at least to an extent, be gotten at by looking at the scope and scale of the “National Archives”. The archives are where we save the incredible mountain of “important paper” the government generates. And it must have some interest in preserving the actual “source documents”.

The sheer volume is almost certainly too much to just automatically copy and file everything and the fact that, in this case, they are important documents requiring security suggests that copying them might be the wrong thing to do. If you have a document you need to keep safe and secure copying it doubles your difficulty.

Also, even if there is a “copy vault”, remember the scale here. This is, apparently, a HUGE collection of documents covering, obviously, a decade or more put in place for a particular purpose. Anyone looking to “hide” information for some near or mid-term timespan doesn’t necessarily need to eliminate all copies – simply eliminating the copies available in the one place where people are actually looking would likely be sufficicient.

Let’s just say, for the sake of exposing the point I’m trying to make, that there is some huge cache of documents about a very important matter. You suspect (or know because you were directly involved in the generation or review of those documents) that some notes were scribbled here and there on some small number (or even just the drafts of one of the documents sure to be in the cache) by various key people you wish to protect. It is the cache that people are poking around in that represents any danger over any meaningful timeframe. The same pile of documents in some distant “protective redundancy vault” are not particularly dangerous because they’re just collecting dust – nobody is poking around through that pile.

If you can remove the documents of concern from the pile that is being poked at, and do so without anyone realizing the documents are gone, then you’ve accomplished your mission – at least for any timeframe that would be of interest. If some historian someday realizes the “poked at pile” doesn’t match the “stored for redundancy and safety pile”, so what. You and the people you are trying to protect are long gone by then or the issue is so old that it no longer matters.

Like I said, just knuckleheaded speculation.