Noted French left-wing activist Thierry Meyssan's 9/11 conspiracy book, L'Effroyable Imposture, became a best-seller in 2002. But I never imagined such an "appalling deception" would ever find a voice in America. At a recent public lecture I was buttonholed by a Michael Moore–wannabe filmmaker who breathlessly explained that 9/11 was orchestrated by Bush, Cheney, Rumsfeld and the Central Intelligence Agency as part of their plan for global domination and a New World Order. That goal was to be financed by G.O.D. (Gold, Oil, Drugs) and launched by a Pearl Harbor–like attack on the World Trade Center and the Pentagon, thereby...