World-war leaders misread deterrent signals

The world wars provide catastrophic examples of great powers misunderstanding what other states were communicating. Hitler entered Poland without expecting the action to produce a wider war. Kaiser Wilhelm II likewise issued Austria-Hungary a blank check without grasping that Britain would become involved in the First World War. The British fleet's concentration in harbor did not communicate enough danger to alter his judgment. A deterrent fails when a leader discounts the commitment behind the signal, even if substantial military power is available.