Page:CIAdeceptionMaximsFactFolklore 1980.pdf/13

C00036554 they are all at the same level of generality. In formulating these, several balances had to be struck — balances between generality and usefulness, level of abstraction and interest, breadth versus detail and the like. Doubtless other observers or analysts would phrase these somewhat differently and/or shift the balance of emphasis among them. Nonetheless, it is felt that these serve as a useful first approximation to build theory upon.

Maxim 1: Magruder' s Principle — the Exploitation of Preconceptions
It is generally easier to induce an opponent to maintain a preexisting belief than to present notional evidence to change that belief. Thus, it may be more fruitful to examine how an opponent's existing beliefs can be turned to advantage than to attempt to alter these views.

Perhaps the most striking application of this principle in military deception is to be found in the selection of the invasion site and cover plan for the D-Day invasion at Normandy. It is well established that Hitler and most (but not all) of his senior military