We read in Parashat Behaalotekha of the mitzva to sound silver chatzotzerot (trumpets) during times of war (10:9), a mitzva which applies even to times of other grave crises (see Rambam, beginning of Hilkhot Ta’aniyot). 

            The Magen Avraham (576) raises the question of why this mitzva is not observed nowadays during times of crisis.  Why should the mitzva to sound trumpets not apply in our times? 

            Numerous answers have been suggested by later writers (most of which are cited and discussed by Rav Eliezer Waldernberg in Tzitz Eliezer, 11:16).  The Peri Megadim suggested that since the Torah introduces this command by describing a situation of enemy attack on Eretz Yisrael (“Ve-khi tavo’u milchama be-artzekhem”), it stands to reason that the mitzva applies only in the Land of Israel.  Of course, as noted by the Chida (in Machazik Berakha) and others, this does not explain why even communities in Eretz Yisrael do not observe this mitzva. 

            The Maharam Shick (on Sefer Ha-mitzvot, 385) answers this question by noting the comments of Talmidei Rabbenu Yona in Masekhet Berakhot that the Torah obligation of sounding the chatzotzerot applies only to crisis situations that threaten the majority of the Jewish nation.  During other crises, according to Talmidei Rabbenu Yona, there is only a rabbinic obligation to sound the chatzotzerot (or a shofar) as part of the public fast day service that would be held in response to the situation.  The Maharam Shick notes the well-known principle of “ein ta’anit tzibur be-Bavel” (Ta’anit 12b), which means that the Babylonian communities did not observe formal “ta’aniyot tzibur” fasts.  (Several differences exist between the formal ta’anit tzibur fast and the fasts we occasionally observe from daybreak to nightfall.)  Among the reasons given for this rule is because the declaration of a formal ta’anit tzibur requires the recognized authority of a Nasi, which was present in Eretz Yisrael but not in Babylonia.  Accordingly, nowadays, when we do not have a Nasi, even in Eretz Yisrael formal ta’aniyot tzibur are not observed (see Mishna Berura 575:25).  The Maharam Shick thus maintains that since the sounding of chatzotzerot in situations that do not threaten the majority of the nation is required only in conjunction with the special ta’anit tzibur observance, it is not practiced nowadays, when we do not conduct this special service. 

            Rav Yaakov Emden, in his Mor U-ktzi’a, notes that the mitzva requires that the chatzotzerot be sounded by kohanim, and he thus suggests that since kohanim nowadays cannot definitively verify their ancestry, the mitzva cannot be performed.  However, later writers questioned this theory, and claim that according to this rationale, today’s kohanim should nevertheless sound the chatzotzerot in case they are truly kohanim and are thus obligated in this mitzva. 

            The Arukh Ha-shulchan (O.C. 576:4) answers by noting that the verse in which this mitzva is presented is immediately followed by a command to sound the chatzotzerot to accompany the sacrificial offerings in the Mikdash.  It stands to reason, the Arukh Ha-shulchan contends, that since the command to sound the trumpets at times of war is introduced in conjunction with the obligation to blow as the sacrifices are offered, it applies only during the times of the Beit Ha-mikdash.  Indeed, as Rav Waldenberg cites, the Sefer Ha-chinukh (384) combines these two commands – to sound trumpets in times of crisis, and during sacrificial offerings – into a single mitzva, and concludes his discussion by asserting that this mitzva applies only during the time of the Mikdash.  This might likely be an early source for the Arukh Ha-shulchan’s claim that the two commands related to the chatzotzerot are linked to one another, and thus even the obligation to sound the trumpets during wartime does not apply after the Temple’s destruction.  (See a similar theory in Iggerot Moshe, O.C. 1:169.) 

            Moreover, Rav Waldenberg notes that the Semag, in his listing of the mitzvot, does not include the mitzva to sound the chatzotzerot during times of crisis.  Later commentators suggested that the Semag interpreted the verse here in Parashat Behaalotekha not as a command, but rather as a promise that when we sound the trumpets and turn to God in sincere prayer, “you shall be remembered favorably before the Lord your God and will be delivered from your enemies.”  According to the Semag, then, sounding the chatzotzerot is not a mitzva at all.