That's the logical fallacy known as affirming the consequent.

Let p be the proposition that the document was forged with MS. That obviously entails the possibility of doing so (q): p --> q.

But you can't infer from q to p. Ab esse ad posse valet consequentia, a posse ad esse non valet consequentia, as the good ol' scholastics would say.

What you need to show is that the document couldn't have been produced using equipment available at the time whence it ostensibly derives. Check out the link I provided upthread for an argument that it could.

The whole MS thing is at most a heuristic with no real evidentiary force. Furthermore, the analysis I linked to (which I'm not admittedly not qualified to evaluate) claims that MS Word can not in fact convincingly emulate the document.

I personally lean agnostic, but if I were forced to place a bet, my kroner would be on authenticity.

The world's northernmost desert wind.

If you believe the documents were forgeries written with Microsoft Word, read this dKos diary - it also mentions the differences between MS Word and IBM Times New Roman fonts I referred to.

An exhaustive analysis of those other Bush documents that were released by the White House can be read here. This is an analysis based on the Air Force and recruitment office regulations of the time, which found evidence of a number of violations - change in status without Bush fulfilling the requirements, mandated disciplinary action or status change not implemented, even fudging with dates and designations.

When I checked on the claims in the WaPo by myself, I looked at a document from this White House-released material, one with multiple lines from different typewriters - this one (click for large version):

Check the second entry, for 4Sep68. What do I see? A raised ^th, which according to WaPo was rare, yet here it is in a not even variable-spaced font. Next, compare the seventh and eighth entries. You'll see the different t-s, l-s, U-s, f-s and 1-s. Also check t-s and f-s in this Killian document and compare them with Microsoft Word's...

Finally, here are the letter typefaces of IBM's Selectric typewriter:

_{*Lunatic*, n.
One whose delusions are out of fashion.}