Defensive War

Excerpted and reprinted with permission from S’VARA 2:1 (1991).

The Jewish rationale for defensive war emerges in a talmudic discussion of when it is permissible to wage war on the Sabbath: 

“Rav Judah stated in the name of Rav: ‘If foreigners besieged Israelite towns, it is not permitted to sally forth against them or to desecrate the Sabbath in any other way on their account,’ and a Tannaitic source teaches the same thing. This, however, applies only where they came for the sake of money matters, but if they came with the intention of taking lives, the people are permitted to sally forth against them with their weapons and to desecrate the Sabbath on their account. Where the attack, however, was made on a town that was close to a frontier [the loss of which would constitute a strategic danger to the other parts of the country], even though they did not come with any intention of taking lives but merely to plunder straw or hay, the people are permitted to sally forth against them with their weapons and to desecrate the Sabbath on their account.” (Eruvin 45a)

Why is Self-Defense Permitted?

This passage establishes a justification for engaging in a category of war not mentioned in Deuteronomy 20 or in the talmudic analysis of obligatory and discretionary wars. Significantly, there is no explicit, biblical justification for engaging in defensive war. The rabbis do establish a duty of self‑defense for each individual on the basis of Exodus 22:1. As the Talmud puts it, “[I]f someone comes to kill you, get up early in the morning to kill him first.” (Berakhot 58a; Yoma 85b; Sanhedrin 72a) Because each individual has both the right and the obligation of self‑defense, one might reasonably infer that the community does likewise.

Rabbi J. David Bleich, however, points out that there are significant problems in justifying defensive war in that way because of the restrictions placed upon the individual’s right of self‑defense. Even if we expand our vision to encompass the obligation that each Jew has to intervene to stop a pursuer (rodef) from killing another person, we cannot, according to R. Bleich, find grounds from such instances of individual action to justify defensive war on this basis.

Bleich gives three reasons for his claim. First, because the obligation to stop the pursuer does not apply when that would endanger one’s own life. Specific sanction beyond application of the law of pursuit is required in order to justify conscription, that is, coercion to endanger one’s life in defending others.

Second, moreover, the law of pursuit may be invoked only in the face of imminent danger to life, but the Talmud sanctions defensive wars against border settlements even when the marauding forces seek only “straw or hay.” Therefore additional sanction is necessary to justify a defensive war to ward off aggression when danger to life is not imminent.

And finally, under the laws of self-defense and pursuit, the intended victim, and even more so a third party, may stop an attacker only if innocent bystanders will not simultaneously be killed, for as the Talmud says, “How do you know that your blood is redder than the blood of your fellow?” Because war, including defensive war, inevitably involves casualties among noncombatants, however, engaging in defensive war requires justification beyond that extended to an individual’s self‑defense, or to a third party to defend an intended victim.

All of the sources that Bleich cites in restricting the rights of self‑defense and of intervention against a pursuer, however, are medieval. The Talmud itself does not limit these rights in that way.

Indeed, despite the cogent grounds that Bleich raises to discriminate the cases, the Talmud in the passage cited above clearly establishes the right and the duty to engage in defensive war. It does not connect the right and duty of communal self‑defense with individual self‑defense or intervention against a pursuer, but neither does it consider Bleich’s arguments as an impediment against establishing both the right and the duty of communal self‑defense.

Expanding the Parameters of Self-Defense

The standard codes not only follow suit, they expand upon this. Thus Maimonides broadens the conditions under which it is permissible to construe the enemy’s action as hostile so as to permit desecrating the Sabbath in communal self‑defense, and he adds the command to aid fellow Israelites caught in a war‑-adding the right to desecrate the Sabbath in returning home after action against the enemy.

“If foreigners besieged Israelite towns, if they came for monetary reasons, it is not permitted to desecrate the Sabbath on their account and we do not make war against them [on the Sabbath]. In a city near the border, however, even if they came only for straw or hay, we sally forth against them with weapons and desecrate the Sabbath because of them. In any location, if they came with the intention of taking lives, or if they established the lines for war, or if they simply besieged us, we sally forth against them with weapons and desecrate the Sabbath because of them. It is a commandment incumbent on all Israelites who can go out and come to the aid of their fellow Jews caught in a siege and to save them from the hand of foreigners on the Sabbath, and it is forbidden to wait until the Sabbath is over. And when they save their brothers, they may return with their weapons to their residences on the Sabbath. [This permission is given] so that they will not be deterred [from aiding fellow Jews] in the future.” (Maimonides, Mishneh Torah, Laws of the Sabbath 2:23)

Joseph Karo, in the Shulkhan Arukh, goes yet further. He proclaims that we sally forth against the enemy on the Sabbath when they come with the intention of taking lives “or even when they simply sally forth against the Israelites with weapons.” That is, we assume that if they have weapons, they intend to take lives.

He also notes, “There is an opinion that in our times, even when the foreigners come only for monetary gain, we sally forth against them on the Sabbath, for if the Jews do not let the non‑Jews despoil and plunder their possessions, they will kill the Jews.” (Shulkhan Arukh, Orah Hayyim 329:6, 7)

In sum, even though the Talmud and codes do not directly connect communal self‑defense to the duty of either defending oneself or intervening on behalf of another, and even though one might argue that the latter duties do not establish the former, the Talmud does not question that a community must defend itself and even desecrate the Sabbath in the process. The codes not only endorse that right, but expand upon it.

These sources also do not insist on the usual procedures required for engaging in other types of war when it is a matter of communal self‑defense.

What About Preemptive Attacks?

To this core case of defensive wars we could add the category of obligatory wars, mentioned in the tractate Sotah [44b], undertaken for the purpose of “diminishing the heathens so that they do not march against them.” This form of defensive war is preemptive in the sense that it is aimed not at an actual attack, but against those who might well attack.

Surprisingly, Maimonides omits this category in his summary of the law of war. This omission has led later commentators to speculate about the permissibility of preemptive defensive war. A range of opinions supports discretionary war to “diminish the heathens” provided the talmudic procedural requirements are satisfied.

Because these requirements, including consultation of the priestly breastplate, the urim vetumim, are inapplicable under modern conditions, the only relevant addition would be an obligatory war to defend Jews against both actual and potential aggression “…even when there is only a suspicion that they may attack us.” (Arukh HaShulkhan He’Atid, Hilkhot Melakhim74:3-4)