Definition
An "analogy" is an inference that if two or more things agree with one another in some respects they will probably agree in others, states Merriam-Webster's online Dictionary. The mental operation underlying analogy---apprehending how things may be associated---plays an essential role in the human mind along with the complementary ability to see how things differ (discrimination), suggests philosopher William James in his book "The Principles of Psychology."
Distortion
Analogizing, if unaccompanied by adequate discrimination, can distort perceptions. In the years immediately preceding World War One, dominant French generals tended to analogize France's military situation to that of 1792 when, supposedly, attacking with zest absent careful defensive preparations led France to victory, notes historian Barbara Tuchman in her book "The Guns of August." By 1914, however, the change in battlefield realities showed that what had worked in 1792 could now prove disastrous. Similarly, Iraqi leader Saddam Hussein analogized Iraq's situation in 1991 to that of North Vietnam in the 1960s, claiming that Iraq in the war over Kuwait would, like North Vietnam, exhaust the U.S., observes Peter Rodman in his book "More Precious Than Peace."
Deception
Policy makers in democratic countries can use analogies to mislead their own citizens by magnifying some threats while obscuring others. In 2002, while preparing the U.S. to invade Iraq, Secretary of Defense Donald Rumsfeld analogized Saddam Hussein to Adolf Hitler in 1938, notes Russ Hoyle in his book "Going to War." With this analogy, Rumsfeld implied that Saddam was preparing to use biological, chemical or nuclear weapons not only against his neighbors but, possibly, against the U.S., even though the U.S. had no hard evidence that Saddam possessed such weapons of mass destruction.
Delusion
People can use analogies to spin fantasy worlds detached from reality. By analogizing the coalition arrayed against him to that arrayed against Frederick the Great in the 18th century, Adolf Hitler in 1945 nurtured the absurd hope that Germany's enemies would drop out of the war, leaving his battered Reich still standing, notes historian John Keegan in his book "The Second World War." An honest assessment of the military situation in April 1945 would have revealed that the British, Americans and Soviets would stay together at least long enough to vanquish the Nazis.