During a war, one must do everything possible for the sake of victory, on Shabbat as well. One may not delay matters by referring questions to rabbis, nor should he bother commanding officers by asking them what is or is not necessary. Rather, anything required must be done as quickly as possible.
In contrast, in normal times, when routine and ongoing security operations and intelligence-gathering are being carried out, Shabbat desecration should be minimized. Only activities meant to prevent life-threatening situations should be undertaken. When possible, it is preferable to use a shinui or another method that renders these actions prohibited on the rabbinic level only. To that end, the military rabbinate of the Israel Defense Forces (IDF) must establish special Shabbat procedures that enable each soldier to carry out his security operations while minimizing Shabbat desecration. Normally, one may not conduct training exercises on Shabbat. Only when forces are on high alert and there is a security need may soldiers be trained for an upcoming operation in which they will participate.
When things function properly, one may rely on a commanding officer’s familiarity with both security needs and halakha, in accordance with the directives of the military rabbinate. Then, if he gives an order that entails Shabbat desecration, the implication is that it is necessary for security needs and must be obeyed. However, when there is reason to distrust the officer – whether because he does not take the rabbinate’s directives seriously, because the rabbinate is not fulfilling its responsibilities, or because the order is illogical – the soldier must clarify with his commanding officer whether the action requested is necessary for security. If, despite what the officer says, it is clear to the soldier that the order involves Shabbat desecration that is not necessary to maintain security, he may not obey the order, as one may not desecrate Shabbat except to save a life. If the soldier is uncertain, he must follow the order, because even the possibility of saving a life overrides Shabbat. However, after Shabbat he must clarify with the army rabbinate, and if necessary with his own rabbis, whether the order was legitimate or not. If it was not, he must file a complaint against his commanding officer and object to his actions, using all avenues available to him.
The primary way to determine if the purpose of an army operation is connected to piku’aĥ nefesh is to see how the army actually relates to the operation. If all week long it is taken seriously and viewed as indispensable to security, and it is carried out even if it involves missing rest time or canceling an entertainment program, then it may be done on Shabbat. However, if all week long it is not taken seriously, and the operation is sometimes canceled for the sake of convenience, then there is no license to desecrate Shabbat in order to do it.
. See the previous note. In an all-out war, R. Goren maintains that Shabbat is suspended. Even according to those who disagree and argue that Shabbat is only superseded, we must avoid doing anything that might prolong the war. As we saw above in sections 4-5, a shinui should not be used if it may delay victory, either now or in the future. In contrast, in normal times, when one can wait patiently to undertake an activity, he should minimize Shabbat desecration as much as possible. For example, one should begin with the least severe prohibition, similar to how a sick person should eat on Yom Kippur (SA 619:7-8). Rema YD 155:3 and Bi’ur Ha-Gra ad loc. 24 extend this principle to medical treatments in general. See above in 18:2, where we discuss when writing is necessary on Shabbat and how to minimize the prohibitions involved. See also Ha-tzava Ka-halakha 16:26 with n. 51, and 17:8.
. It is difficult to define what level of danger justifies desecration of Shabbat, since there are endless dangers. Even routine life is full of danger – on the roads, while going for a walk, and even while climbing a ladder at home. Even the flu can become life-threatening on rare occasions. Nevertheless, we do not hospitalize everyone who contracts the flu. The rule is that if something is generally considered dangerous, and people take serious, directed action to avoid it, it is considered a danger for which one desecrates Shabbat. This is the position of R. Isser Yehuda Unterman in Shevet Mi-Yehuda 1:19:2, as quoted in SSK ch. 32 n. 2. R. Shlomo Zalman Auerbach and R. Eliezer Waldenberg (Tzitz Eliezer 9:17:8:22) agree with this position. Thus we can generally establish the halakha based on how people relate to the danger all week. See Ha-tzava Ka-halakha 16:8, 13, 14, 16-19.