A variety of conspiracy theories question the mainstream account of the September 11, 2001 attacks in the Unite States. At the least, these theories posit that the official report on the events is not sufficiently forthcoming, thorough or truthful. Many critics allege that individuals in the government of the United States knew of the impending attacks and intentionally failed to act on that knowledge. Some critics state that the attacks could have been a false flag operation carried out by high-level officials in the U.S. government who may have engaged compartmentalization to keep knowledge of their actions limited. The common suspected motives were the use of the attacks as a pretext to justify overseas wars, to facilitate increased military spending, and to restrict domestic civil liberties.