The Clinton administration reacted to intelligence like this with, for example, requiring that airlines single out no more than two arabs per flight for search. Think about it---you get intelligence that terrorists will use airliners to attack NYC targets and you react by making it more difficult for airport security to protect planes.
IOW, the intelligence that the Clinton administration had was not met with corrective action, was not met with inaction. INSTEAD it was met with actions to FACILITATE terrorist.