The U.S., Preemption and International Law

Economic sanctions, cyber defense, targeted killings and cyberwar may delay Iranian nuclear weapons manufacture and deployment, but they won't stop it altogether.

International law is not a suicide pact. Fashioned to ensure the survival of states in a still-anarchic world, this binding system of rules includes the "inherent" right to national self-defense. Such right may be exercised not only after an attack has occurred but also, sometimes, in advance. This sensitive legal issue is now especially critical in the refractory case of Iranian nuclear weapons development. Could preemption in this case be permissible under international law?

Although plainly less prominent in the Obama administration than in the Bush era, preemption remains a codified part of American military doctrine. Valid customary law permits a first use of force if the danger posed is "instant, overwhelming, leaving no choice of means and no moment for deliberation." Drawn from an 1837 event known as the "Caroline affair," which concerned the unsuccessful rebellion in Upper Canada against British rule, this doctrine builds upon the classic formulation of Hugo Grotius. Self-defense, says the Dutch scholar in "The Law of War and Peace" (1625 ), may be permitted "not only after an attack has already been suffered, but also in advance, where the deed may be anticipated." In a 1758 text, Swiss jurist Emmerich de Vattel affirmed: "A nation has the right to resist the injury another seeks to inflict upon it, and to use force and every other just means of resistance against the aggressor."

Interestingly, for Americans, the works of Grotius and Vattel were favorite readings of Thomas Jefferson, who relied heavily upon them in crafting the Declaration of Independence.

Article 51 of the UN Charter - though it limits self-defense to circumstances following an attack - does not override the customary right of anticipatory self-defense.

We should also recall Article VI of the U.S. Constitution, and assorted U.S. Supreme Court decisions. All proclaim unambiguously that international law is part of the law of the United States.

The Caroline Doctrine notes an implicit distinction between preventive war (which is never legal ), and preemptive war. Even the latter is not permitted merely to protect oneself against an emerging threat, but only when the danger posed is "instant" and "overwhelming."

Using such a literal framework, it would first appear doubtful that the United States could now construct a current and compelling legal argument for preemption against Iran. This would be the case even if the planned American defense operation were limited meticulously and precisely to nuclear military targets.

Yet, we no longer live in the 17th, 18th, 19th or 20th centuries. Grotius, Vattel and those later jurists who were focused on the attack on the Caroline could never have anticipated the genuinely existential risks posed in the 21st century by a nuclear Iran. The permissibility of anticipatory self-defense is understandably much greater in the nuclear age. Today, waiting passively to absorb a nuclear attack could be clearly suicidal. A particular danger is posed by terrorist groups serving as surrogates: If not prevented from receiving nuclear weapons or fissile materials from patron states, such proxies (e.g., Hezbollah, Hamas, Al-Qaida ) could inflict enormous damage upon targets.

Israel is the country at greatest risk from Iranian nuclear weapons. Significantly, however, there is a long and venerated international legal tradition that Great Powers have commensurately great responsibilities.

The United States is presently the only country that has the operational capability to undertake a successful preemptive mission to remove Iran's covert and illegal nuclear weapons program. In the best of circumstances, such an expression of anticipatory self-defense would be broadly multilateral, and endorsed by the United Nations. But we don't yet live in the best of all possible worlds, and even now, the most likely alternative - if there is not an American defensive strike on Iran - would be a fully nuclear Iran, led by irrational Shiite clerics. Should this alternative be "selected," America would need to clarify persuasively that its response to any attack on the United States or its vital interests in a Middle East where nuclear weapons are now proliferating would be instant and overwhelming.

In world politics, irrational does not mean "crazy." It indicates, rather, that national self-preservation is valued less than certain other leadership preferences. With Iran, these preferences would be associated with various core religious beliefs and expectations.

There can be no foreseeable nuclear balance of terror in the Middle East. In the not-too-distant future, Iran could well justify using nuclear weapons against "infidels" or "apostates," whatever the expected retaliatory consequences. In such conceivable cases, nuclear deterrence would be ineffective. Iran would become a suicide-bomber writ large; in other words, a "suicide-state."

Two successive administrations, those of both Bush and Obama, publicly pledged, as official U.S. policy, that a nuclear-armed Iran would be unacceptable. If we are to take this bipartisan pledge seriously, we must now finally acknowledge that sanctions alone will not work. At the same time, operationally, it is already very late for anticipatory self-defense against Iran. Latest IAEA reports indicate that Iran has begun to move critical nuclear materials to special underground bunkers.

In any event, preemption would now come at a very high cost. But, we also need to inquire: What would be the alternative to allowing a militarily nuclear Iran? Economic sanctions, cyber defense, targeted killings and all-out cyberwar may effectively delay Iranian nuclear weapons manufacture and deployment, but they won't stop it altogether.

Shall we take our presidents at their word on such urgent matters? If so, even at this 11th hour, we must be fully prepared to compare the expected costs of all available options, and then choose accordingly.

Louis René Beres is professor of political science and international law at Purdue University. He chaired Project Daniel in Israel. Admiral (ret. ) Leon "Bud" Edney served as vice chief of U.S. naval operations; NATO supreme allied commander, Atlantic; and commander in chief, U.S. Atlantic Command. Lt. Gen. (ret. ) Thomas G. McInerney, served as vice chief of staff, USAF; deputy chief of staff for operations and intelligence; and vice commander in chief, HQ, U.S. Air Force in Europe.