As evidenced by the emergence of websites such as WhatReallyHappened.com, 911Truth.org, and ScholarsFor911Truth.org (among many others), the post-9/11 period saw the rise of a formidable movement contending that the widely accepted version of what had occurred on September 11, 2001 was nothing more than a disinformation campaign hatched by the U.S. government which was itself responsible for the death and destruction.
These conspiracy theorists believe that somehow the Bush administration, with the collusion of the Pentagon, either carried out the attacks or simply permitted them to happen, so as to justify the subsequent establishment of a quasi-police state wherein civil liberties could be severely curtailed.
The conspiracists contend that United Flight 93, which crashed into a field in rural Pennsylvania, was not brought down by the heroism of passengers who tried to regain control of the cockpit from the hijackers, but rather was shot down by U.S. fighter pilots. Likewise, the conspiracists maintain that airliners could not possibly have toppled the World Trade Center (WTC) towers or the nearby 7 WTC building in New York, but that their collapse was the result of controlled demolitions orchestrated by government-affiliated plotters. In a similar vein, they say that the Pentagon was struck not by an airplane but by a U.S. missile.
Yet another belief popular among 9/11 conspiracy theorists is the notion that the attacks were the result of an international Jewish plot that somehow involved Israel. Citing, among other alleged pieces of evidence, a 2001 Jerusalem Post article describing the Israeli government's post-9/11 efforts to account for its missing citizens in the area of the World Trade Center and the Pentagon, conspiracists suggest that the Mossad (Israel's intelligence agency) forewarned some "4,000 Jews" employed in the WTC about the impending attacks, prompting them to stay home from work on September 11th and thereby escape harm.
One notable 9/11 conspiracy theorist is the French leftwing activist and author Thierry Meyssan. In his books L'Effroyable Imposture (The Big Lie) and Le Pentegate, Meyssan posits an alternative scenario for American Airlines Flight 77 and the attack on the Pentagon. Citing the seeming disappearance of the plane after it struck the building -- and the relatively small amount of resulting debris that could be positively identified -- Meyssan posits that the U.S. government essentially attacked itself by using either a truck bomb, a smaller airplane, or a missile to hit the Pentagon.
Other prominent 9/11 conspiracy theorists include Rep. Cynthia McKinney, actor Charlie Sheen, actor Ed Asner, activist Medea Benjamin, comedienne Janeane Garofalo, psychologist and author John Gray, professor Richard Falk, environmentalist Randall Hayes, rabbi Michael Lerner, professor Mark Crispin Miller, consumer advocate and political figure Ralph Nader, and the former Obama administration "green jobs czar" Van Jones.
Adapted from "The Truth About 9/11 Conspiracy Theories," by Cinnamon Stillwell (San Francisco Chronicle: April 19, 2006)