The big questions these days are whether Israel will attack Iran’s nuclear facilities and, if yes, when.

That Iran’s having nuclear weapons poses an existential threat to Israel is clear from its statements, although doubts remain as to whether Iran actually would do so considering the danger to the rest of the region. Nuclear clouds know no borders.

KEEPING THE FAITH: One religious perspectIve on issues of the dayOn the other hand, to the extent that the missiles that began raining down on Israel last weekend from the south – some this week coming perilously close to Tel Aviv – are being hurled by Iranian puppets presumably with Tehran’s approval, a case can be made that Iran has already launched a war against Israel, albeit a conventional one. How does Israel respond, according to Jewish law, and, if a military response is permitted, what are the rules of engagement?

Jewish law recognizes the existence of two kinds of war: the obligatory war and the discretionary, albeit divinely sanctioned, one. Obviously, this implies a third category – the discretionary war with no sanction, meaning an “illegal war.” David’s war of conquest against Syria may be such an “illegal war.” (See Sifre to Deuteronomy, Piska 51.)

Clearly, there are no “rules of engagement” for an illegal war. Any deaths that occur in the course of such a war are considered to be outright murder.

As for the two legitimate categories, the Talmud describes them this way: “The wars waged by Joshua to conquer [Canaan by defeating the seven nations present there at the time] were obligatory…, [while] the wars waged [with divine sanction] by the House of David for territorial expansion were discretionary….” (See the Babylonian Talmud tractate Sotah 44b.)

The eternal war against Amalek must also be regarded as obligatory, because the Torah says so (see Exodus 17:14-16 and Deuteronomy 25:17-19). If obligatory wars can be fought only against the “seven nations” or Amalek, obligatory wars in our day are not possible. Maimonides, however, expands the category. Rambam, as we prefer to refer to him, labels as obligatory any war that is “fought to assist Israel from an enemy that attacks it” (see Mishneh Torah, The Laws of Kings and Their Wars, 5:1). Again assuming that Iranian surrogates are responsible for the current missile attacks, a war against Iran becomes obligatory.

There is a problem, however: Rambam does not explain how he came to add something not found either in the Torah or the Talmud (a not uncommon problem with Rambam’s citation-less code).

Ostensibly, Rambam based it on two Torah verses. The first, Numbers 10:9, recognizes the need to “go to war in your land against an enemy who oppresses you.” The second commands one not “to stand idly by the blood of your neighbor” (Leviticus 19:16).

“Idly by” is seen as a commandment to take direct action in order to protect another person from physical harm, especially if it could lead to the person’s death. Since “an enemy who oppresses you [in your land]” is threatening deadly physical harm to the citizens of that land, Rambam apparently sees defending against that enemy as an obligatory war.

That may not be how Rambam got there, however. He simply may have come down on one side of a talmudic debate regarding pre-emptive wars (see BT Sotah 44b). In the debate, one side saw pre-emptive wars as obligatory; the other side saw them as discretionary. A pre-emptive war presumably is one in which there is reasonable certainty that the enemy plans to attack; thus, it is also defensive. If such a war, almost certainly fought outside the land, is obligatory, then surely a defensive war fought after an enemy has attacked must be obligatory. Missiles fired on Israel by Iranian surrogates qualify as attacks.

Rambam 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 describes the defensive war as a “commanded” one (milchemet mitzvah) and the other two as “obligatory” (milchamot chovah). Post-Rambam decisors also make this distinction, although some practical (but insubstantial) differences exist in how wars in each “subcategory” are fought.

This brings us to the terms of engagement.

The first rule, it seems, is to offer an enemy a chance to make peace, although it is not clear whether this applies across the board. (See Deuteronomy 20:10.) Rambam claims that this applies to both obligatory and discretionary wars (see MT, Kings, 6:1). Others disagree with him as far as obligatory wars are concerned. (Maimonides also maintains that this requirement applies even to Amalek, whom we are to “blot out from under the heaven,” according to Deuteronomy 25:19.)

Nachmanides (the Ramban) concurs with Rambam. His position also can be supported by the teachings of some talmudic sages. States Rabbi Yosi the Galilean, “Even in a time of war, one must initiate all activities with a request for peace.” (See Midrash Rabbah to Leviticus, Parashat T’zav 9.)

In any case, the entire free world, not just Israel, has given Iran ample opportunity to avoid war. This “term of engagement,” if it actually exists in this case, nevertheless is met.

The second rule, as Maimonides formulates them, is that, once an enemy is surrounded, there must be a way left open for innocent civilians and even faint-hearted combatants to escape. (See MT, Kings, 6:7.) Some authorities (Nachmanides, for one) insist that Rambam meant this to apply to discretionary wars, but there is no such limitation evident in the Mishneh Torah. (Sadly, there is also no suggestion on how such a rule can be made practical.)

The third rule is to leave standing the fruit-bearing trees of the enemy, as demanded by Deuteronomy 20:19. Maimonides notes that this applies to everything that is beneficial to people, but only if there is destructive intent. Thus, “anyone who breaks utensils, tears garments, destroys buildings, stops up a stream, or ruins food with destructive intent transgresses the command….” (See MT Kings 8 and 10.)

The key, of course, is the phrase “destructive intent.” The destruction has to be wanton, not purposeful.

This will allow for collateral damage, to use the neutral term that describes a horrific consequence, but would provide any “punishing” attacks that are common in such wars.

Those are the rules. Let us pray they are not needed.