The great enemy of truth is very often not the lie -- deliberate, contrived, and dishonest -- but the myth -- persistent, persistent, pervasive and unrealistic. John F. Kennedy
I recently ran across this quote, and thought it true, especially when related to the political climate in the United States. Myth is definitely more potent than lies because it is, often, not questioned. After a while, especially in politics, it is taken as fact by its proponents and any attempt to rectify the belief shunned or completely ignored.
These political myths tend to occur in the most radical elements at both ends of the political spectrum. Those elements tend to listen to only those proponents of these myths and take their statements without questioning the factual basis of the statements. This allows no room for compromise as they are unwilling to listen to any statement which contradicts the myth.