Having read the declassified PDB, we now know the answer to President Bush’s rhetorical question, “Some have said we must not act until the threat is imminent. Since when have terrorists and tyrants announced their intentions, politely putting us on notice before they strike?”
Apparently, the answer is “When the President goes on vacation”:
Nevertheless, FBI information since that time indicates patterns of suspcious activity in this country consistent with preparations for hijackings or other types of attacks, including recent surveillance of federal buildings in New York.