A preemptive strike is a military action which is designed to neutralize a potential threat, or to gain a distinct advantage against an enemy. The legality of preemptive strikes is questionable, as they are generally considered offensive actions except in very specific circumstances. For example, a preemptive strike against troops massing near a nation's border might be considered justified, while a random airstrike on a known enemy might not be legally acceptable. Despite debates over the legality of such actions, many nations throughout history have used preemptive attacks as military tools.
When a preemptive strike is considered, several things are usually incorporated into the decision. The first is a careful examination of the nature of the threat, with concrete threats like troop buildups or detonations of nuclear devices being considered justifications for preemptive attacks. Analysts also think about the likelihood of an anticipated attack from an enemy, weighing things like public announcements, intelligence information, and historical activities by the enemy.
Generally, governments are also encouraged to consider alternatives before moving on to a preemptive strike. When weighing the decision to make such a strike, government officials look at other options like diplomacy, sanctions, and other tools. Ideally, an aggressive action should only be undertaken if all other options have been exhausted. Finally, analysts may consider legal and ethical justifications for such a strike, to see if it conforms with the terms of the United Nations Charter.
For the striking nation, a preemptive attack can be a powerful military tool, especially if it is carried out well. The opposing nation can be unbalanced and surprised by the attack, thus giving the attacking nation the upper hand. The goal is to prevent further military action with a show of force, but a preemptive strike can also weaken an enemy's military abilities, which can be an advantage in a prolonged war or military action. A preemptive strike also requires far less military personnel than a conventional attack or invasion.
Several governments prefer preemptive attacks to actual declarations of war, because these declarations may require the participation of legislatures, which takes time. A preemptive strike can be authorized by the head of state and rapidly carried out, which creates an element of surprise and minimizes public debate over the issue. However, legislatures and citizens may hold their governments accountable for such strikes, and United Nations members may also be expected to justify their preemptive attacks in an international forum.