What are we to make of the failed Underwear Bomber plot, the Toothpaste, Shampoo, and Bottled Water Bomber plot, and the Shoe Bomber plot? These blundering and implausible plots to bring down an airliner seem far removed from al-Qaida's expertise in pulling off 9/11.
If we are to believe the U.S. government, Khalid Sheikh Mohammed, the alleged al-Qaida "mastermind" behind 9/11, outwitted the CIA, the NSA, indeed all 16 U.S. intelligence agencies...
And so on.
Consider the logic of this line of argument. If a terrorist plot is successful, it couldn't have been terrorists, because terrorism against the United States is hard to pull off. It is difficult, therefore impossible. Apparently, 9/11 deniers are convinced that Middle Eastern Muslims can not possibly be as clever as white Westerners.
If a terrorist plot fails, 9/11 deniers say, it is because terrorists are incompetent dolts, uneducated foreigners who could not possibly possess the capacity for tactical action required to pull off this sort of thing. I mean, just look at how many ridiculous plots have been foiled!
It never seems to occur to 9/11 deniers that recent events prove that there are many, many attempts made on the lives of Americans at home and abroad on a constant basis, and that the probability of a terrorist attack succeeding is positively correlated with the amount of planning that went into it. With many attempts tiny probabilities stack, and those who plan win. Those would be those snippets of obvious statistical reality that are just too inconvenient for deniers to pay attention to.