At the beginning of the Iraq war only 38% of Americans said the war was justified even if Iraq did not have weapons of mass destruction. When no such weapons were found after the war, 58% of Americans then supported the war. This revision of people's memories of the government's rationale for going to war is as an example of

Cognitive dissonance.

Explanation:

This is described to be the discomfort that is been experienced between two conflicting beliefs, social values or even human behaviours. Inconsistencies of this kind seen between people's believe and how they behave motivates people to engage in actions that will help minimize feelings of discomfort. Research has also noticed that attempts to relieve this tension in different ways, such as by rejecting, explaining away, or avoiding new information.

Factors that could show a person is affected by cognitive dissonance include:

Uncomfortable feelings before doing something or making a decision. Another is the rationalizing of a certain decision made by you.

Feeling embarrassed or ashamed towards your acts.