Israeli officials have recently ramped up their arguments for striking Iranian nuclear facilities. So far, there has been silence among Jewish religious thinkers about whether attacking Iran would be consonant with Jewish values.

So what would Judaism say about such a military action? Would God want us to attack Iran?

The Jewish tradition does not speak with one voice on the ethics of war, and distilling this complex issue in this forum risks oversimplification. Still, I understand the tradition to point in a particular direction. Here’s why:

In our time, the only war Jewish law permits is defensive war. True, Jewish law theoretically allows Jews to wage an “optional war” to conquer territory or to demonstrate military prowess. But since we no longer have a Sanhedrin (an ancient rabbinic court) or Urim V’tummim (priestly oracles), these wars are currently forbidden, even if they might eventually help protect Jewish lives.

Maimonides defines a defensive war as one waged “to assist Israel from an enemy that has come upon them” (Laws of Kings 5:1). The plain meaning of this ruling is that the only permissible war (in fact, it is called an “obligatory war”) is one to repel an attack and to defend lives that are in danger. Moreover, in order to qualify as a defensive war, the enemy must initiate the aggression.

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Those standards may have worked in ancient and medieval milieus. Invading armies could be spotted from a distance and appropriate defenses could be mustered in sufficient time to resist attacks and defend the population. But in the contemporary context, when the push of a button and a single missile can kill thousands within minutes, many authorities have expanded the definition of a defensive war to include preemptive actions.

In this more liberal definition, an adversary no longer has to invade or fire the first shot to be considered as having initiated hostilities. The clear intention to attack becomes enough to give the Jewish people the right and the religious obligation to prohibit the enemy from doing so. Authorities usually base this understanding on the Talmudic dictum, “If one comes to kill you, rise up early to kill him [first]” (Sanhedrin 72a).

However, authorities do not universally agree that this ruling, originally stated regarding an individual’s right to self-defense, applies in the realm of national defense. For instance, Rabbi Aryeh Cohen, a professor of Talmud at Los Angeles’ American Jewish University, argues in his 2008 essay “War is Assur (Forbidden)” that it does not apply to national defense. The scenarios, according to Rabbi Cohen, are too different. While an individual can manage, with relative precision, the violence he uses to defend himself, nations deploy violence on a scale that they can never fully control. Even in the most “surgical” of strikes, there is almost always “collateral damage.”

Rabbi Cohen concludes that all war is forbidden, even defensive wars. His is not the normative approach, but regardless of whether one supports his opinion, the Talmud seems to imply that preemptive defensive action may only harm the would-be aggressor.

Additionally, the Talmud implies one must be certain that the enemy intends to kill and that the murderous act is imminent. The Talmud does not say, “If you think someone is coming to kill you…” or “If someone eventually plans to kill you.” Instead, it places the lethal drive in the present. The hostile is coming to get you, knife in hand, right now. You know he’s coming for you. You know his plan is to kill. Only when that standard is met may you “rise up early to kill him.”

These nuances present challenges for those who endorse attacking Iran. First, can the violence be controlled? Is it possible that innocent people will die? Given the strategic difficulties presented by striking Iran, the challenges of dropping one-ton bombs so surgically as to take out only nuclear targets without killing innocents, and the possibility of an assault triggering a wider conflict, this first question ought to give us serious pause. The medicine cannot be worse than the disease.

Secondly, and perhaps most importantly, does Iran meet the Talmud’s standard for preemptive killing? Iran is clearly developing nuclear technology, but do we know Iran is planning to build a weapon? No, we do not. And even if we knew that Iran plans to build a nuke, do we know it plans to use it? No. And even if we knew that Iran planned a nuclear attack, do we know its intention is to kill Jews or destroy Israel? No. And even if we knew that Iran planned to attack Israel, do we know that it is imminent? No; most experts believe Iran is still years away from building a weapon. The Talmud implies that we may not “rise up early to kill first” unless those standards are met.

With the American war in Iraq still fresh in our collective memory, Judaism’s standards for just wars become especially poignant. A decade ago, Bush Administration officials began calling for military action against Saddam Hussein. They contended that Hussein had secret weapons stockpiles, was producing weapons of mass destruction, and was supplying weapons to terrorists. Given Hussein’s belligerent attitude toward the West, his defiance of the international community, and his track record of brutality at home and abroad, these pieces of evidence were, at the time, offered to prove a clear and imminent threat to the U.S.

So the U.S. invaded, igniting a nearly ten-year war that reportedly resulted in more than 150,000 deaths. Only amid the rubble and corpses did we discover that most, if not all, of the arguments in favor of the war were false. We let fears, not facts, govern our decisions. Our goal was to save innocent lives; we took many, instead.

The Talmud teaches that, in 586 BCE, Judea was destroyed not because its defenses were too weak, but because the Jews were indifferent about shedding blood (Shabbat 33a). Let us pray that history does not repeat itself.

Michael Knopf is the Assistant Rabbi of Har Zion Temple in Penn Valley, Pennsylvania, and a recent graduate of the Ziegler School of Rabbinic Studies in Los Angeles.

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