As we have already learned, since we no longer suffer from harsh decrees and religious persecution, and on the other hand, the HolyTemple is still in ruins, the status of the minor fasts currently depends on the will of the Jewish people. Just as the very obligation to fast depends on Israel’s desire, so do the [other] laws of the fast. And when the Jews accepted upon themselves to fast during the intermediary period, they did not agree to treat these fasts as strictly as the Yom Kippur fast. This is the fundamental difference between the three minor fasts and Tish’a B’Av. Because so many troubles befell us on the ninth of Av, we are obligated to fast on that day even during the intermediary period, and its laws remain as originally established: i.e., the fast lasts an entire day and we are enjoined – among other things – to afflict ourselves by not bathing, applying ointments, wearing shoes, and engaging in marital relations, just like on Yom Kippur.
However, the laws of the other fasts that were instituted as a result of the churban are more lenient. We fast only during the day and we are only prohibited from eating and drinking, not bathing etc.
Another difference: pregnant and nursing women must fast on Tish’a B’Av; only the infirm are exempt. On the three minor fasts, however, even pregnant and nursing women who are healthy are exempt from fasting, because when the Jews originally agreed to fast on these days, they decided to be lenient with these women, [ruling that] they need not fast (SA OC 550:1-2).
Preferably, one should act strictly and refrain from bathing in hot water during the fast, but one may wash in lukewarm water for purposes of cleanliness. It is also inappropriate to take a haircut, listen to joyous music, or shop for things that make one happy during the fast.
However, some [authorities] maintain that Jews must observe full-day fasts in every generation during periods of [anti-Jewish] decrees and religious persecution. This seems to be the simple understanding of the Talmudic discourse as explained by the Ramban and the other poskim. That is, whenever there are [harsh] decrees, the obligation to fast returns to its original status and the three fasts take on the laws of Tish’a B’Av. The Tashbetz (2:271) concurs, but he writes that if the persecutions affect part of the Jewish people, only they need to fast an entire day. It is possible, though, that even they are [exempt from this stringency, seeing that they are considered] “under duress” because of the persecutions.
The Shelah writes in Tractate Ta’anit (Ner Mitzvah 6) that it would have been appropriate to act strictly [and treat] all three fasts like Tish’a B’Av, but we do not impose an enactment upon the people unless they can bear it. Therefore, [the rabbis] ruled strictly only with regard to Tish’a B’Av. Sefer HaPardes, attributed to Rashi, indicates that an individual who feels that he can tolerate it should fast an entire day on all the fasts. He concludes that it is good to act strictly only in the area [of eating], while it is unnecessary to observe the other afflictive prohibitions; and if one wishes to act strictly, he should do so in private, to avoid arrogance. The Magen Avraham and many other Acharonim mention this [ruling]. Apparently, they understood that since [evil] decrees existed in their times, it was appropriate to act strictly on the three fasts, but [the masses] did not conduct themselves in this manner. Therefore, individuals who are capable of acting strictly should do so. The reason [Sefer HaPardes] ruled leniently regarding the other restrictions is that their status is more lenient from the start. After all, many poskim maintain that these restrictions are not forbidden by Torah law even on Yom Kippur. The Magen Avraham and Mishnah Berurah (550:6) write that the only area in which one should not be strict is wearing shoes, because it would look ridiculous [to walk around without shoes when everyone else is wearing them], implying that it is good to act stringently in the areas of washing, anointing, and the like. I believe that their reasoning is based on the fact that there were so many [harsh] decrees, as I wrote above, and the Sha’ar HaTziyun (9) concurs. (See Rabbi Karp’s Hilchot Bein HaMetzarim 1:8, where he makes an inference from the words of the Gra. In my humble opinion, however, he did not read the words of the Shelah and the Acharonim carefully enough, thinking that they ruled stringently even in the intermediary situation, when it appears that they were strict only because of the [harsh] decrees [that prevailed at the time]. See also Piskei Teshuvot 550 6-7, [and note] 22.)
Either way, in our times, after the establishment of the State of Israel (with God’s help), it seems that there is no reason whatsoever to act strictly. We are obligated to fast, regardless of the nation’s will, only when there are [harsh] decrees, according to the Ramban, or religious persecutions, according to the Tashbetz and the Tur. If there are no such troubles, however, everyone agrees that we do not have to fast [on the three minor fast days] as we do on Tish’a B’Av. And even if we explain that the Shelah meant to say that the Jewish people would have accepted [the three fasts] as full fasts, if they were able to do so, even in the intermediary situation, which depends on Israel’s will, and therefore individuals should fast the entire day; nevertheless, there is no room whatsoever to be strict in the current State of Israel, where – thank God – we are not even subjugated to the nations of the world. After all, Rashi holds that the fasts are completely nullified when we are free from the yoke of the nations. Albeit, most Rishonim disagree with Rashi (see note 1, above), but it is impossible to transform a situation which Rashi considers joyous into one of completely obligatory fasting. Therefore, there is no room to be strict and fast an entire day and observe the other afflictive prohibitions on the three fasts as is done on Tish’a B’Av. This goes against what is written in Torat HaMo’adim (1:4) and Hilchot Chag BeChag (1:3).