Why were the united states pacific fleet and other military installations caught off guard?

At the start of WWII nobody expected a Japanese surprise attack in that great of numbers. Also without radar (which was just starting) or someone trailing them- nobody knew where the Japanese fleets were.

Hey there! something that is given up as the result of a choice is referred to as  a decisionwhen you have a choices that are being refereed, this would mean that this would be a decision.~jurgen