Victory disease occurs in military history when complacency or arrogance, brought on by a victory or a series of victories, makes an engagement end disastrously for a commander and his forces.
A commander may disdain the enemy, and believe his own invincibility, leading his troops to disaster. That commander may employ strategies that, if effective in earlier combats or maneuvers, prove catastrophic against a new or smarter enemy. The commander afflicted by "victory disease" may also fail to anticipate that a new enemy may use tactics different from those of old enemies. An overconfident commander may disregard military intelligence that would enable the commander to realize that new tactics are needed.
Though "victory disease" does not inevitably foretell defeat, it often precedes it. The term is also applied outside the military world in areas such as psychology, business, or marketing.
Origin
The origin of the term (, in Japanese) is associated with the Japanese advance in the Pacific Theater of World War II, where, after attacking Pearl Harbor in 1941, Japan won a series of nearly uninterrupted victories against the Allies in Southeast Asia and the Pacific.
Much of Japan's arrogance is attributed to the performance of Admiral Matome Ugaki. From overriding decisions to ignoring the evolving conflict in the Pacific, Ugaki's tactics incited tension and doubt in other Japanese military personnel before the Midway operation.
Although the Japanese had planned to establish a perimeter and go on the defensive, victories encouraged them to continue expanding to an extent that strained logistics and the navy. This culminated in the Battle of Midway in 1942, a catastrophic defeat of the Japanese navy. All four Japanese aircraft carriers involved were sunk, and the hitherto unstoppable Japanese advance was blunted.
History
Pre-modern
The hubris of Xerxes I led to a catastrophic defeat of the Achaemenid Empire in the Battle of Salamis, which occurred in 480 BC. This was the turning point of the Greco-Persian Wars and the ancient Greeks, who the Persians were opposing, eventually won. The ancient Greek playwright Aeschylus fought in the battle; he wrote the play The Persians in which the Battle of Salamis is a setting. In 1415, at the Battle of Agincourt, the English were outnumbered between three and five to one, but the disorganization of French knights, as well as superb quality longbows, were the underlying circumstances which led to the English overcoming the odds and annihilating the French. The overconfidence and lack of preparation led to the disastrous defeat of the English, led by Edward II at the Battle of Bannockburn to the Scots, led by Robert the Bruce. The Spanish naval assault on England in 1588 suffered the defeat of the Spanish Armada. Similarly, English overconfidence the following year led to the disaster of the English Armada.