1973 Document Puts Bush on Guard Base (washingtonpost.com)
The White House has released a document that, it says, proves George W. Bush really did turn up for duty with his Air National Guard squadron in 1973. Unfortunately, it's the record of a dental examination taken on the 6th of January 1973, which proves that he visited his base at least on that day. But nothing else, except of course for the condition of his teeth.
One might be forgiven for thinking this not entirely sufficient, especially as the White House spokesman contradicted a presidential offer to open his entire ANG personnel file. The Calpundit is worth reading on the whole affair - being the blogger who broke much of the current row when he got his hands on a key document.