The most worrisome aspect of these revelations has to do with the credibility of the "Air Force One is next" message. It is described clearly as a threat, not a friendly warning — but if so, why would the terrorists send the message? More to the point, how did they get the code-word information and transponder know-how that established their mala fides?
That knowledge of code words and presidential whereabouts and possession of secret procedures indicates that the terrorists may have a mole in the White House — that, or informants in the Secret Service, F.B.I., F.A.A. or C.I.A. If so, the first thing our war on terror needs is an Angleton-type counterspy.