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Soon facing Iranian nuclear missiles

The United States, preemption, and international law

By Professor Louis René Beres
Admiral Leon “Bud” Edney
General Thomas G. McInerney


For now,  the “Arab Spring” and its aftermath still occupy center-stage in the Middle East and North Africa. Nonetheless, from a regional and perhaps even global security perspective, the genuinely core threat to peace and stability remains Iran. Whatever else might determinably shape ongoing transformations of power and authority in Tunisia, Egypt, Libya, Syria and Saudi Arabia, it is apt to pale in urgency beside the steadily expanding prospect of a nuclear Iran.

Enter international law. Designed, inter alia, to ensure the survival of states in a persistently anarchic world – a world originally fashioned after the Thirty Years War and the Peace of Westphalia in 1648 – this law includes the “inherent” right of national self-defense. Such right may be exercised not only after an attack has already been suffered, but, sometimes, also, in advance of an expected attack.

What can now be done, lawfully, about relentless Iranian nuclear weapons development?  Do individual states, especially those in greatest prospective danger from any expressions of Iranian nuclear aggression, have a legal right to strike first defensively? In short, could such a preemption ever be permissible under international law?

For the United States, preemption remains a part of codified American military doctrine. But is this national doctrine necessarily consistent with the legal and complex international expectations of anticipatory self-defense?

To begin, international law derives from multiple authoritative sources, including international custom. Although written law of the UN Charter (treaty law) reserves the right of self-defense only to those states that have already suffered an attack (Article 51), equally valid customary law still permits a first use of force if the particular danger posed is “instant, overwhelming, leaving no choice of means and no moment for deliberation.” Stemming from an 1837 event in jurisprudential history known as the Caroline, which concerned the unsuccessful rebellion in Upper Canada against British rule, this doctrine builds purposefully upon a seventeenth-century formulation of Hugo Grotius.

Self-defense, says the classical 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 his later text of 1758, The Right of Self-Protection and the Effects of Sovereignty and Independence of Nations, 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.”

Article 51 of the UN Charter, limiting self-defense to circumstances following an attack, does not override the customary right of anticipatory self-defense.  Interestingly, especially for Americans, the works of Grotius and Vattel were favorite readings of Thomas Jefferson, who relied  heavily upon them for crafting the Declaration of Independence of the United States of America.

We should also recall Article VI of the US Constitution, and assorted US Supreme Court decisions. These proclaim, straightforwardly, that international law is necessarily part of the law of the United States.

The Caroline notes an implicit distinction between preventive war (which is never legal), and preemptive war. 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 could first appear doubtful that the United States may now construct a persuasive legal argument for preemption against Iran. This would be the case even if the planned American defense operation were carefully limited to exclusively nuclear military targets.

Nonetheless, we live in very different times. Grotius, Vattel and those later jurists who were focused on the Caroline could never have anticipated the genuinely existential risks soon to be posed by a nuclear Iran.  Understandably, the permissibility of anticipatory self-defense is far greater in the nuclear age than in prior centuries. Today, after all, it is easy to imagine, simply waiting impotently to suffer an enemy nuclear attack could be entirely irrational. Even suicidal.

A  special danger is posed by terrorist group surrogates. If not prevented from receiving nuclear weapons or fissile materials from patron states, such proxies (e.g., Hezbollah, Hamas, al-Qaeda) could inflict enormous harms upon targets that would be out of range of nuclear-tipped missiles.

The United States is not the only country at risk from Iranian nuclear weapons. Israel is at greater risk. There is, however, a long and respected international legal tradition that Great Powers have proportionately great responsibilities. This would suggest, from a management of world power standpoint, that America must remain ever-mindful of a potential nuclear threat to other, far smaller states.

We are presently the only country that may still have an operational capability to conduct a successful preemptive mission against Iran’s illegal nuclear weapons program.  Ideally, such a resort to anticipatory self-defense would be broadly multilateral, and also formally endorsed by the United Nations. But, we don’t yet live in an ideal world, and, even now, the most plausible alternative to any American defensive strike on Iran would likely be a fully nuclear and possibly irrational Iran. Should this non-preemption scenario be allowed to play out as actual policy, America, in compensation for its new strategic vulnerabilities, would then need to clarify that its response to any attack on the U.S. or its vital interests and allies in the Middle East would be instant and overwhelming.

In the precise language of contemporary 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 closely associated with various fundamental religious beliefs and expectations.

It is unlikely that we could ever see a stable nuclear balance of terror in the Middle East. Rather, in the foreseeable future, Iran – irrespective of any expected retaliatory consequences – might conceivably justify using nuclear weapons against certain “infidels” or “apostates.” In such realistic cases, nuclear deterrence, of course, would be immobilized.

Iran, in these cases, would become a suicide-bomber writ large; a “suicide-state.”

Two successive administrations, 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, it may already be very late for anticipatory self-defense to work against Iran.

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

International law is not a suicide pact. Even now, even after so much critical time has already been wasted with regard to mounting effective defensive measures against Iran, anticipatory self-defense should not be dismissed out of hand. If, after all, the calculated benefits of any such option were judged to exceed the expected gains of all other available options, such a lawful preemption would still emerge as America’s rational or preferred choice.

Louis René Beres (Ph.D., Princeton, 1971) is the author of many books and articles dealing with nuclear weapons and international law. He is Professor of Political Science and International Law at Purdue University. Read his previous OUPblog posts here.

Leon “Bud” Edney, Admiral  (U.S. Navy/ret.) served as Vice Chief of Naval Operations; NATO Supreme Allied Commander, Atlantic; and Commander in Chief, U.S. Atlantic Command. Admiral Edney, who holds an advanced degree from Harvard, was also Distinguished Professor of Leadership at the U.S. Naval Academy.

Thomas G. McInerney, Lt.General (U.S.A.F./ret.), served as Vice Chief of Staff, USAF; Deputy Chief of Staff for Operations and Intelligence; and Vice Commander in Chief, Headquarters, U.S. Air Force in Europe. General McInerney is co-author (with Maj. Gen. Paul Vallely), of  Endgame: The Blueprint for Victory in the War on Terror.

For further reading, we recommend Nuclear Energy: What Everyone Needs to Know.
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Recent Comments

  1. Adina Kutnicki, Israel

    Living in Israel, the epicenter of Iran’s nuclear wrath, I can think of no better expert to advise my government than Professor Beres. The notion that they will ignore his strategic doctrine is too awful to contemplate.

  2. […] Enter international law. Designed, inter alia, to ensure the survival of states in a persistently an… […]

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