Surprise attack and the challenge of intelligence early warning are familiar topics with which both academic and professional intelligence circles have been grappling extensively and intensively. The reason is clear: a military attack on a state is a painful experience that often causes military and other significant damages to the target, sometimes to the point of a crushing defeat.
If an attack is carried out without the target's prior anticipation, it becomes a surprise attack. Its damages are more severe than if the target had been at a higher level of preparedness. The surprise factor significantly increases the aggressing party's chances of military success, because it prevents the target from utilizing the full potential of its military and other capabilities, which in other circumstances might have been able to contain the attack and cope with it effectively. Aside from the military–technical dimension, surprise attacks usually produce a panic and/or a paralyzing shock that embraces all the systems of leadership and command, and may even spread to the entire nation. This element may be no less significant than the military advantage provided by the surprise.
Surprise attacks, such as Pearl Harbor in 1941, the Yom Kippur War in 1973 or the terror attack on September 11, 2001, were perceived as traumatic events on the national level and became an ongoing focus of public and scholarly attention. Hence, in the modern era, states have set up intelligence mechanisms aimed at preventing surprise attacks.