An American War with Iran: Legal and Strategic Implications for Israel Commentary
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An American War with Iran: Legal and Strategic Implications for Israel

In apparent response to US President Donald Trump’s unilateral American withdrawal from the July 2015 Iran Pact (JCPOA), the Islamic Republic has seemingly reinvigorated its active nuclear program. In turn, this has led to a more-or-less continuing cycle of threat and counter-threat between the two adversarial countries, and has been reinforced by both US Secretary of State Mike Pompeo and National Security Advisor John Bolton. In upcoming months, it is entirely plausible that a precipitating event (e.g., another commercial ship seizure by Iran) would set the spark for an Iran-US war. Inevitably, as the following article makes clear, such a war could quickly involve US ally, Israel. What then?

For the most part, if US President Donald Trump goes to war with Iran, core policy issues will center on pertinent matters of strategy and tactics, and not law. Nonetheless, these complex issues are frequently overlapping and interpenetrating. At times, wittingly or unwittingly, operational war decisions could be jurisprudentially determinative.

For example, depending upon which country were to strike first in the increasingly adversarial and belligerent US-Iran context, American military actions could become either law-violating or law-enforcing.

Similar legal judgments would necessarily follow from the particular types of weapons used and from their corresponding regard or disregard for non-combatant (civilian) populations.

None of this is meant to suggest that any first use of force by either party must be prima facie illegal. This is the case, inter alia, because customary international law (defined at Article 38 of the UN’s Statute of the International Court of Justice) expressly allows for certain residual resorts to “anticipatory self defense.” Following The Caroline (1837), international law need never be taken as some form or other of a suicide pact.

There is more. International law is always a part of each state’s domestic or municipal law, an authoritative incorporation most conspicuous for the United States at Article 6 of the US Constitution (the Supremacy Clause) and in various US Federal Court decisions, especially the Paquete Habana (1900) and Tel Oren v. Libyan Arab Republic (1981).

But there are certain antecedent questions. What, precisely, does US President Trump have in mind for any prospective armed conflict with Iran? And what would this presumptive American expectation really mean for US ally, Israel?

Once a war were genuinely underway between Iran and the United States, full-scale military engagements could quickly and substantially involve Israeli armed forces (IDF). In certain plainly worst case scenarios, these clashes would involve assorted unconventional weapons and could directly impact Israel’s vulnerable civilian populations. The most fearful worst case narratives, of course, are those that would involve nuclear ordnance.

In anticipation, capable strategic and jurisprudential thinking are both required. Even during a potentially fleeting time that Israel remained the only regional nuclear power, an American war with Iran could still elicit Israeli nuclear deterrence threats and/or Israeli nuclear reprisals for enemy-inflicted harms. For Israel, moreover, such threats or reprisals could be entirely rational.

How might such dissembling circumstances emerge, as a “bolt-from-the-blue” spasm of violence, or in less blatant stages, that is, in difficult to fathom increments of harm? Most credibly, perhaps, a “collateral war” would come to Israel as a catastrophic fait accompli, a multi-pronged belligerency wherein even the most comprehensive security preparations in Jerusalem/Tel-Aviv could suddenly prove inadequate. What could happen next, both operationally and legally?

The only meaningful answer to such inherently problematic queries must be candid affirmations of strategic unpredictability. In science and mathematics, accurate statements of probability must be drawn systematically from the discernible frequency of relevant past events. Significantly, however, in those increasingly dense strategic matters currently before America and Israel, there are no relevant past events.

None at all.

Strategically, there is more to ponder. For the moment, at least, Donald Trump has favored no tangible military doctrine. Accordingly, once confronted with a “no doctrine” war launched against Iran by this American president, whether as a defensive first-strike or as a retaliation (both could conceivably be lawful), Israel’s senior strategists would need to fashion their own corresponding doctrines ex nihilo.

How precisely should Jerusalem/Tel Aviv most accurately anticipate Iranian or Iranian-surrogate attacks on Israeli targets? As an antecedent question, how should these decision-makers and planners best identify which of these vulnerable targets would be judged presumptively “high value”? At some point, such an Intelligence Community/Ministry of Defense (MOD) operational challenge could even include the small defending country’s Dimona nuclear reactor.

Israel is less than half of the size of America’s Lake Michigan.


In both 1991 and 2014, the ultrasensitive facility at Dimona had already come under rocket and missile attack from deliberate Iraqi and Hamas aggressions respectively.

In any upcoming war with the United States, Tehran would likely (but incorrectly) regard direct attacks upon selected Israeli targets as proper “retaliations” for American strikes – whether these strikes were an initial move of war against the Islamic Republic and its surrogates or a more-or-less foreseeable response to Iranian first strikes. Here, too, Iranian forces could potentially gain operational access to hypersonic rockets or missiles. Should this access be obtained, Israel’s critical capacity to shoot down hypersonic glide vehicles (HGVs) and/or hypersonic cruise missiles (HCMs) might subsequently prove inadequate.

What would happen next? Plausibly, any considerations of law and justice would only be anterior to national considerations of victory and survival.

In essence, when the pertinent options are examined dialectically, as they should be, it could be to Tehran’s perceived advantage to ostentatiously drag Israel into any US or Iran-initiated war. Striking the US homeland itself would prove vastly more difficult for Iran, and also more likely to elicit variously intolerable reprisals. Clearly, a Trump-initiated war against Iran would strengthen Saudi military power specifically and Sunni Arab military power in general. While such an expected strengthening might now seem less worrisome to Israel than expanding Iranian militarization, this delicate strategic calculus could change very quickly.

In this case, Israeli planners would need to investigate a number of previously disregarded military options against specific Sunni Arab adversaries, including pertinent legal questions of both jus ad bellum and jus in bello.

Should the Trump-led American military find itself in a two-front or multi-front war – a complex conflict wherein American forces were battling in Asia (North Korea) and the Middle East simultaneously – Israel could unexpectedly find itself fighting on its own. For such an exceptionally complicating scenario to be suitably appreciated, Israeli strategists would first need to bear in mind that the “whole” of any deterioration caused by multi-front engagements could effectively exceed the sum of constituent “parts.”

This means, among other things, that Israeli strategists and planners will need to remain aptly and persistently sensitive to all conceivable synergies. In this connection, it goes without saying that the Trump administration is unaccustomed to such challenging intellectual calculations. Somehow, for these planners in Washington, complex strategic decision-making can best be extrapolated from the commerce-driven worlds of real-estate bargaining and casino gambling.

It would be far better for Washington and Jerusalem to recall the timeless insights of Carl von Clausewitz. For the author of On War, the determining standard of reasonableness in any military contest must always lie in its presumed political outcomes. For a state to get caught up in war – any war – without any clear political expectations is a mistake, always, or prima facie.

For more years than we may care to recollect, futile American wars have been underway in Iraq and Afghanistan. In time, for both Iraqis and Afghans, once-hoped-for oases of regional stability will regress to what seventeenth-century English philosopher Thomas Hobbes would have called a “war of all against all.” At best, what eventually unravels in these severely fractured countries will be no worse than if these wars had never even been fought.

This will not be a desired political outcome.

Shouldn’t we now inquire, accordingly: Shall Americans sacrifice so much blood and treasure merely to bring about a status quo ante bellum?

Over the years, with the now obvious exception of North Korea, America’s principal doctrinal enemy has changed, dramatically, from “communism” to “Islamism” or “Jihadism.” This time, however, the ideological adversary is palpable, real and not merely presumptive. This time, also, it is a formidable and finely-textured foe, one that requires serious analytic study, not ad hoc responses or seat-of-the-pants presidential eruptions. At times, to be sure, real or contrived bellicosity can helpfully serve American national security policy objectives, but not where it is wholly detached from any previously-constructed theoretical foundations.

There is more. The Jihadist enemy of Israel and America remains a foe that can never be fully defeated, at least not in any tangibly final sense. To wit, this determined enemy will not be immobilized on any of the more usual or traditional military battlefields.


If at some point a particular Jihadist adversary has seemingly been vanquished by US military forces in one country or another, it will likely re-group and reappear elsewhere. After Iraq, after Afghanistan, even after Syria (which now winds down with US and Russian support of a genocidal regime that has been historically hostile to Israel), America will face resurgent adversaries in hard-to-manage and geographically far-flung places. These locales include Sudan, Mali, Nigeria, Yemen, Somalia, Egypt, and perhaps even Bangladesh or (in the future) “Palestine.”

Daily, in the Middle East, an American president and his National Security Advisor are sounding alarm bells over Iran – and this after the United States, not Iran, withdrew from an international legal agreement that was less than perfect, but (reasonably) better than nothing at all.

When all these intersecting factors are taken into suitable intellectual account, there remains a residual argument (one that might quickly be anticipated in Israel) that a US generated war with Iran would de facto amount to an anti-nuclear preemption or to some similarly purposeful act of “anticipatory self-defense.” Here, and with little reasonable doubt, the American war would be widely regarded as “cost-effective” or “net gainful” in Jerusalem/Tel Aviv. This visceral assessment, however, could become more a matter of what Sigmund Freud called “wish fulfillment” than of any serious strategic assessment of risks and benefits.

Plausibly, there could be only a tiny likelihood that American bombs and missiles would be adequately targeted on widely multiplied/hardened/dispersed Iranian nuclear infrastructures.

In reality, at least at present, a US war against Iran would be contrary to Israel’s core national security interests and obligations. Glib reassurances to the contrary from Jerusalem or Tel Aviv or Washington (or from both capitals) could be prospectively lethal for Israel. Though assuredly genuine, the threat from Iran should never be taken as an opportunity for simplifying political rhetoric. Instead, this threat should be assessed and calibrated dialectically, as reliably as possible according to normally verifiable standards of enemy force posture estimations.

If, at any point during crisis bargaining between Iran, Hezbollah, Israel and the United States, one side or the other should place too great a value on achieving “escalation dominance” and too little on parallel considerations of national safety, the expanding conflict could quickly turn “out of control.” Such consequential deterioration would be especially or even uniquely worrisome if Israel threatened or actually launched some of its presumptive nuclear forces. This is the case, moreover, irrespective of any promised strategic support for Israel from the United States.

In sum, if Israel should look to the United States for seamlessly capable geo-strategic leadership, it would be taking very great and genuinely unprecedented national security risks. At a minimum, Israel has the incontestable right (and also the obligation to its own citizens) to expect fully decipherable expressions of US military doctrine. Going forward, unless it should insist more firmly upon maintaining this critical right, Israel could sometime have to face starkly injurious security outcomes. Here, the prospect of a fully-sovereign Palestinian state would need to be taken as a potentially important “intervening variable.”

Every state’s first responsibility is to assure and maintain citizen protection, and citizen allegiance is therefore contingent upon such valid assurances. Most famously in pertinent political theory is the classic statement of seventeenth-century Englishman Thomas Hobbes, at Chapter XXI of his Leviathan: “The obligation of subjects to the sovereign is understood to last so long, and no longer, than the power lasteth, by which he is able to protect them. Later, Thomas Jefferson, third president of the United States, described this obligation as binding upon all the nations. Writing his Opinion on the French Treaties (April 28, 1793), Jefferson opined: “The nation itself, bound necessarily to whatever it’s preservation and safety require, cannot enter into engagements contrary to its indispensable obligations.”

There is more. In law, every state has an enduring obligation to oppose and (if necessary) suitably punish aggression. Indeed, punishment of aggression is a longstanding peremptory expectation of international criminal law. The foundational principle of Nullum Crimen sine poena, “No crime without a punishment,” has its origins in the Code of Hammurabi (c. 1728 – 1686 B.C.E.); the Laws of Eshnunna (c. 2000 B.C.E.); the even earlier Code of Ur-Nammu (c. 2100 B.C.E.) and the law of exact retaliation, or Lex Talionis, which is presented in three separate passages of the Jewish Torah.

For Israel, a uniformly continuous concern with certain basic jurisprudential principles could advance its legal as well as strategic objectives, most plainly those that William Blackstone had identified in his Commentaries on the Law of England (Book 4 “Of Public Wrongs”): “Each state is expected, perpetually,” noted Blackstone, “to aid and enforce the law of nations, as part of the common law, by inflicting an adequate punishment upon the offenses against that universal law.”

Such ideas did not arise in a theoretic or intellectual vacuum. Moreover, Blackstone is ultimately indebted to Cicero’s antecedent description of natural law in The Republic: “True law is right reason, harmonious with nature, diffused among all, constant, eternal; a law which calls to duty by its commands and restrains from evil by its prohibitions….” Natural law lies at the very heart of United States Constitutional law, and all that is derived therefrom.

As for “just wars” pertaining to both jus ad bellum and jus in bello criteria, Hugo Grotius wrote that they “arise from our love of the innocent.” Though it is most unlikely that such legal high-mindedness could ever factor into US President Donald Trump’s possible decision to encourage or initiate war against Iran, it remains a promising standard for Israel to bear closely in mind. This will prove especially good advice if American military actions against Iran should sometime prod the Islamic Republic to “retaliate” against Israel.


Louis René Beres (Ph.D., Princeton, 1971) is Emeritus Professor of Political Science and International Law at Purdue. A frequent contributor to JURIST, he also publishes in BESA Perspectives (Israel); Israel Defense; Parameters: Journal of the US Army War College (Pentagon ); The War Room (Pentagon); Modern War Institute (West Point); Special Warfare (Pentagon); Yale Global Online; Harvard National Security Journal (Harvard Law School); World Politics (Princeton) and The Bulletin of the Atomic Scientists. Professor Beres is the author of many books and articles dealing with international relations and international law. His twelfth and latest book is Surviving Amid Chaos: Israel’s Nuclear Strategy (Rowman & Littlefield, 2016((2nd. ed., 2018). In 2016, he co-authored a major policy monograph at Tel Aviv University with US General (USA/ret.) Barry McCaffrey: Israel’s Nuclear Strategy and America’s National Security. Professor Beres was born in Zürich, Switzerland, on August 31, 1945.


Suggested citation: Louis René Beres, An American War with Iran: Legal and Strategic Implications For Israel, JURIST – Academic Commentary, August 13, 2019,

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