The United States and five other nations are trying to talk Iran out of pursuing its nuclear development program; Iran with a nuclear bomb poses an existential threat to states in its immediate neighborhood and to the rest of the world. Iran, after all, is a state sponsor of terrorism worldwide. If it develops nuclear weapons, it is reasonable to assume it will share those weapons with its terrorist friends.

Israel and much of the Arab world find themselves allied in opposition to these talks. Iran cannot be trusted, they say. The only way to insure that Iran does not develop nuclear weapons is to destroy its program, even if that involves going to war.

Jewish law, obviously, binds none of these countries, but on which side of the debate does halacha fall?

At first glance, it would seem to fall on the side of the negotiators.

According to Deuteronomy 20:10: “When you come near a city to fight against it, then proclaim peace to it.” This led Rabbi Yosei the Galilean to say, “Great is peace, since even in wartime, one must not begin [hostilities] except by [first offering] peace.” (See Leviticus Rabbah 9:9.)

In other words, war is the last resort.

There is a catch, however. Beginning with the Torah, sanction is given for the use of deadly force against a potential attacker whose intentions are not clear. Thus, if someone invades your home in the dead of night, and you cannot see whether he is armed, killing that person is justifiable homicide. On the other hand, there is no justification “if the sun has risen,” meaning if you can see that he is no threat to your life. (See Exodus 22:1-2.)

It does not end there. If you know a person is pursuing a third party with deadly intent, you have to stop him by any means possible, including killing him. We derive this from the law in Deuteronomy 22:25-27, which states that a rapist is to be put to death. The language is such that if the only way to prevent a rape is to kill “the pursuer,” the rodef, that is preferable to his completing his crime. As the Babylonian Tractate Sanhedrin 73a-74a explains, if “the Torah decreed that [the potential rape victim] may be saved by the life of her [would-be] rapist,” even though she will survive the attack, how much more so does this apply when someone is actually trying to kill another person?

For the record, as BT Sanhedrin 74b notes, the pursuer may be killed if that is the only way to stop him. If you can talk him out of committing the crime in the first place, for example, the pursuer may not be killed.

This brings us to two other Torah laws that also play a role here. One, Leviticus 19:16, commands us not “to stand idly by the blood of your neighbor.” This is regarded as a commandment to take direct action in order to protect another person from physical harm, especially if that person is in danger of being killed.

The second, Numbers 10:9, recognizes the need to “go to war in your land against an enemy who oppresses you.”

Jewish law recognizes two kinds of war – obligatory ones (wars against the seven Canaanite nations) and discretionary wars with divine sanction (e.g., most, but not all, of David’s wars of expansion).

Regarding the obligatory wars, the eternal war against Amalek is included, since it is mandated by the Torah. (See Exodus 17:14-16 and Deuteronomy 25:17-19.) That would seem to shut down the possibility of obligatory wars in the current day, since neither the seven nations of Canaan nor Amalek exist any longer. Maimonides, however, includes as obligatory a war that is “fought to assist Israel from an enemy that attacks it” (see MT, Kings, 5:1).

He offers no citation to support this. Ostensibly, he based that on the two Torah verses just cited. Maimonides does recognize, however, that there is a difference between the Canaanite/Amalek obligations on the one hand, and defending against attack on the other. Thus, elsewhere, he creates a subcategory, calling a defensive war a “commanded war” as distinct from an “obligatory” one. Other decisors since then have also made this distinction. While there are some practical differences in how wars in each “subcategory” are fought, though, they are not substantial.

Where does this leave us? The United States and its allies are correct in pursuing a peaceful way out of the Iran conundrum. They also, however, must not stand by the blood of their neighbors, meaning Israel and the Arab world. Israel and the Arab world are also correct, however, in seeing Iran as a pursuer. They also are correct in seeing themselves as a homeowner in the dead of night, unable to be certain whether the burglar has a deadly intent.

Give peace a chance, but if there is a reasonable suspicion that Iran is merely stalling until it can develop a bomb, a military solution is the only one.