The _Authoritarian Personality_ folks (esp. Frenkel-Brunswick) argued that this not evolutionary adaptation at all, but traits that developed through particular child-rearing practices, such as rigid discipline, blind following of conventional roles, and parental authority based on brute power rather than principles.
But that may explain only why the 70 or so percent of the American sheeple believe in the AQ-Saddam fantasy. I do not think, however, that Cheney, Rumsfeld or even Bush believe any of this crap which they manufacture for popular consumption. I think the Bushies were pretty certain they would encounter very little resistance because Iraq was weak and had little capacity to wage any substantial warfare, defensive or offensive. This is precisely why the Bush gang decided to attack Iraq - because they though they could do it and get away with it. This flatly belies all claims to the purported "danger to the US security that those fascist creeps ever made.
Wojtek