The achievement of surprise on all levels of war—tactical, operational, and strategic—has always been considered one of the most important ingredients for success in war. As a fundamental principle of war, surprise allows the side that achieves it (usually the attacker, but possibly a defender) to concentrate superior forces unnoticed at the decisive point, and to catch the opponent unprepared (in terms of time, place, method, or new technologies). With his plans thus undermined, the opponent is caught psychologically off balance. Successful surprise enables the destruction of a larger proportion of the enemy forces at a lower cost or faster speed; a successful surprise therefore acts as a powerful force multiplier. At times, the achievement of surprise will provide a weaker side with the only hope of compensating for its deficiencies and the only chance to defeat a more powerful opponent. As a result, great efforts have always been made to achieve surprise through secrecy and concealment as well as through the extensive use of
deception and diversions.
Throughout history, given the shorter time and smaller spaces involved in the lower levels of war, it was almost always possible to achieve tactical and operational surprise. Yet as
Carl von Clausewitz observed, this was far less feasible on the higher strategic level of war. Since the beginning of the twentieth century, the increased mobility, speed, and range achieved by the introduction of railways, the combustion engine (cars), and ultimately, long-range air power and even ballistic missiles have made the achievement of strategic surprise practicable on the strategic level as well. In fact, almost all wars of the twentieth century opened with a surprise attack by the side initiating the war. The ability to achieve strategic surprise has also rendered obsolete the tradition of declaring war before the opening of hostilities. (Such official
declarations of war were last made before the outbreak of
World War I). States initiating a war did not want to lose the considerable advantages to be gained from achieving strategic surprise. Most modern wars are therefore launched by a strategic surprise, which is then sometimes followed by a formal declaration.
The ability to achieve a decisive strategic surprise in the opening stage of a war magnifies volatility in times of crisis; this reciprocal fear of surprise attack in turn creates strong incentives for making the first move or launching a preemptive attack.
Not only has strategic surprise become feasible in the twentieth century, but it has also, at the opening phase of war, become almost impossible to prevent despite the considerable improvement in the capabilities and performance of
intelligence work. (In fact, despite all of the advances in intelligence, it has become even more difficult to prevent the achievement of surprise on the higher strategic and operational levels.) This is demonstrated by the following examples, in which strategic surprise was successful even when all sides were aware that war was likely: Port Arthur (1904); the German attack on Norway (April 1940) and in the west (May 1940);
Barbarossa (1941);
Pearl Harbor (1941); North Korea (June 1950); China in Korea (1950); Britain, France, and Israel (1956); Israel (1967); the Arab states (1973); the USSR's invasion of Czechoslovakia (1968) and of Afghanistan (1979); and Iraq's invasion of Kuwait (August 1990).
Larger-scale surprise could be achieved at sea in earlier periods (for example,
Horatio Nelson at Copenhagen and the Battle of the Nile). Interestingly, in modern times, strategic surprise has been achieved despite the availability of more than enough intelligence information to indicate that a forthcoming attack was planned. Thus, for example, the United States knew before the attack on Pearl Harbor that the Japanese were seriously contemplating war and had read Japanese codes that gave some indication of the imminent attack.
Joseph Stalin received literally hundreds of warnings before the German attack on Russia (June 22, 1941), which he chose to ignore. In the same way, the Israelis had plenty of warnings before the Arab attack in 1973.
This raises a number of serious questions concerning the value and limitations of modern intelligence, a subject that has received much attention, in particular from political scientists. Seven interrelated explanations are worth mentioning here:
Michael H. Handel
Richard K. Betts, Surprise Attack (1982); Michael I. Handel, War, Strategy, and Intelligence (1989); Thomas L. Hughes, The Fate of Facts in a World of Men: Foreign Policy and Intelligence Making (1976).
