If you're going to be a terrorist, you've got to play it cool. In 1999, would-be bomber Ahmed Ressam filled his car with explosives and drove it from Canada to the U.S. border. But at the very moment a customs inspector approached, he panicked and ran away. Naturally, Ressam's freak-out raised suspicion and resulted in his arrest [source: Schanzer].
Ressam isn't the only terrorist whose destructive attempt has been thwarted. In the 12 years since the 9/11 attacks, an estimated 54 other terrorist attacks on the U.S. have failed [source: Zuckerman]. And these are only the attempts we know about, which have been publicly documented through news articles and official briefings. The actual count of "almost" attacks is likely much higher.
Some credit an effective trifecta for keeping the U.S. relatively safe from terroristic harm: police work, intelligence reports and citizens willing to report suspicious activity [source: Avlon]. And sometimes the terrorists themselves bungle the plan. Whatever the strategy to uncover current threats, there are powerful lessons to be found in examining previous plots that have failed. Let's start with one from way back in history.