Previous research shows that a large segment of the U.S. population has maintained factually inaccurate beliefs concerning Iraq for at least a decade after the start of the Iraq war. These beliefs were maintained despite the fact that significant press coverage challenged them, a bipartisan Senate committee denounced them, and no new convincing evidence has surfaced to support them. The authors believe that 2 ideological preferences, authoritarianism and social dominance orientation, provide the motivational mechanisms for individuals to adopt and maintain factually inaccurate beliefs because such beliefs are consistent with their preferences. The authors combine and extend previous research by examining the relationships between authoritarianism and social dominance, the holding of factual misperceptions years after the U.S. military entered Iraq in 2003, and support for the Iraq war and a broader foreign policy of preemption. Using a student sample, they found that those higher in authoritarianism and social dominance orientation held more misperceptions about the Iraq war, which, in turn, predicted support for military engagement in Iraq and for a broader preemptive military policy. The number of misperceptions held partially mediated the effect of authoritarianism and social dominance orientation on support for war. These factual misperceptions serve as justifications for individuals to express their preexisting preferences. This bias makes factually inaccurate perceptions regarding support for war relatively immutable once adopted.