Definitions of cognitive dissonance on the Web:

• An inconsistency among some experiences, beliefs, attitudes, or feelings. According to dissonance theory, this sets up an unpleasant state that people try to reduce by reinterpreting some part of their experiences to make them consistent with the others.
  www.wwnorton.com/college/psych/gman5/glossary/C.htm
• Cognitive dissonance is a psychological phenomenon first identified by Leon Festinger. It occurs when there is a discrepancy between what a person believes, knows and values, and persuasive information that calls these into question. The discrepancy causes psychological discomfort, and the mind adjusts to reduce the discrepancy. In ethics, cognitive dissonance is important in its ability to alter values, such as when an admired celebrity embraces behavior that his or her admirers deplore. Their dissonance will often result in changing their attitudes toward the behavior. Dissonance also leads to rationalizations of unethical conduct, as when the appeal and potential benefits
  www.ethicsscoreboard.com/rb_definitions.html

Definitions of patriotism on the Web:

• Patriotism is a feeling of love and devotion to one's own homeland (patria, the land of one's fathers). This article surveys the concept of patriotism from the viewpoints of history, politics, ethics, and biology.
  en.wikipedia.org/wiki/Patriotism
• The act of being loyal to one’s country, especially in periods of national turmoil, such as war. However, there are many disagreements over what constitutes a patriotic person, exemplified over the burning of the flag.
  www.abateofcolo.org/Tips%20&%20Info/Civics%20Glossary.htm
  

Cognitive dissonance combined with the poor and generally propagandistic grade school education of history in the US creates a context for the irrational, blind and deaf patriotism exhibited by so many Americans.