Preemptive war
A preemptive war is a war that is commenced in an attempt to repel or defeat a perceived imminent offensive or invasion, or to gain a strategic advantage in an impending (allegedly unavoidable) war shortly before that attack materializes.[1] It is a war that preemptively 'breaks the peace' before an impending attack occurs.
Not to be confused with preventive war, namely an anticipatory war in the face of a less immediate threat.
The term 'preemptive war' is sometimes confused with the term 'preventive war'. The difference is that a preventive war is launched to destroy the potential threat of the targeted party, when an attack by that party is not imminent or known to be planned. The U.S. Department of Defense defines a preventive war as an armed conflict "initiated in the belief that military conflict, while not imminent, is inevitable, and that to delay would involve greater risk."[2] A preemptive war is launched in anticipation of immediate aggression by another party.[3] Most contemporary scholarship equates preventive war with aggression, and therefore argues that it is illegitimate.[4] The waging of a preemptive war has less stigma attached than does the waging of a preventive war.[5]
Article 2 (4) of the UN Charter requires that states refrain from the initiation of armed conflict, that is being the first to 'break the peace' unless authorized by the UN Security Council as an enforcement action under Article 42. Some authors have claimed that when a presumed adversary first appears to be beginning confirmable preparations for a possible future attack, but has not yet actually attacked, that the attack has in fact 'already begun', however this opinion has not been upheld by the UN.[6][7]
Theory and practice[edit]
Prior to World War I[edit]
As early as 1625, Dutch jurist Hugo Grotius characterized a state's right of self-defense to include the right to forestall an attack forcibly.[8] In 1685, the Scottish government conducted a preemptive military strike against Clan Campbell.[9] In 1837, a certain legal precedent regarding preemptive wars was established in the Caroline affair, during which an Anglo-Canadian force from Upper Canada crossed the Niagara River into the United States and captured and burnt the Caroline, a ship owned by Reformist rebels. During the affair, an American citizen was killed by a Canadian sheriff.
The British asserted that their actions were permissible under the international law of self-defense. The United States did not deny that preemptive force might be lawful under some circumstances but claimed the facts did not support its use in this case. U.S. Secretary of State Daniel Webster wrote that when a nation uses force "within the territory of a power at peace, nothing less than a clear and absolute necessity can afford ground of justification" and that the necessity for the use of armed force must be "instant, overwhelming, leaving no choice of means, and no moment for deliberation," which conditions did not apply in this case.[10] That formulation is part of the Caroline test, which "is broadly cited as enshrining the appropriate customary law standard."[11]