Why weren't Tzaddok and Baytos put to death?

Question

Why weren't Tzaddok and Baytos, fathers of the Tz'ddokim and Baytosim, put to death as z'kenim mamrim?

Answer 1

By way of getting a clearer understanding of the parameters of a zakein mamre one should refer to Mishna Sanhedrin 11:3 which writes:

There is greater stringency in respect to the teachings of the scribes than in respect to the torah: [thus,] if a zakein mamre [rebellious elder] says, there is no commandment of tefillin, so that a biblical law may be transgressed, he is exempt. [But if he rules that the tefillin must contain] five compartments, thus adding to the words of the scribes, he is liable. This mishnah states that a rebellious elder who teaches against a Rabbinic teaching, one not mentioned explicitly in the Torah, is dealt with more severely than one who teaches against the explicit words of the Torah. An elder who states that there is no commandment of tefillin is not to be executed, since the commandment of tefillin is stated explicitly in the Torah (Exodus 13:9, 16, Deuteronomy 6:8, 11:18). Anyone who hears this elder teach that there is no tefillin will be able to check the Torah and realize that the elder’s teaching is false. However, one who states that the tefillin must be made of five boxes, instead of the four prescribed by the Rabbis, is liable for the death penalty. Since the Torah does not state how many boxes are to be in the tefillin, this is a teaching that if we didn’t know from the Rabbis we would not know at all. Therefore, an elder who teaches against this teaching is more of a threat than the elder who teaches against something stated specifically in the Torah. Note: The tefillin worn on one’s head contain four boxes but the one worn on the arm contains only one box. From the outside each is painted black and therefore looks like one box. (sefaria translation and notation)

Rambam on the Mishna explains this as follows and brings the case of Tzadok and Baytos. (Feel free to help with the translation, I'm not sure I did it proper justice):

There is greater stringency in respect to the teachings of the scribes than in respect to the Torah: They said one is exempt when he admitted being chayav (i.e. liable), but he would cancel/annul them in its teaching like it says, to transgress the words of Torah until he admitted that it was a transgression. And therefore he does not have to die in a court of law since he is not put to death for annulling a מצות עשה (positive mitzvah), but if he said there is no tefillin in the way of heresy, he will be killed on the part that he is a heretic not on the side that he is zaken mamre. And know this matter well, since one who cause doubt amongst the many about the sages - this is what the Talmud classes as a zakein mamre, and they are not chayav until he will say like this, or do like this or make a condition like this. And when they do not complete the condition thereby saving themselves, this is not the case, but can be explained as meaning that he is not obligated as a zakein mamre but rather he is exempt from the judgement of zakein mamre, however he must die because others will think about his differing views and beliefs. Alternatively, he is undoubtedly denying that which is written in the Torah; "Hashem our G-d, Hashem is One", which mean that such a person is not killed or that he is regarded as a zakein mamre, and is definitely killed because he is an exception to the rule. This means, from all of Israel, of which there will be sinners, he is one of the sinners, namely a zakein mamre. And accordingly, there is no zakein mamre who destroys the wall of the Torah and does not deny its acceptance in every facet such as Tzaddok and Baytos. Such a man sees his words as being greater than Beis Din and therefore he is worthy of death for not showing (the proper) respect to Beis Din. This draws parallels with the case of a person who curses his father and mother, who (likewise) we put to death for not showing the (proper) respect to his father and mother. Therefore, a zakein mamre according to a court who wanted a court to forgive him may forgive him, but this is not true for the reason that we mentioned i.e. not to increase arguments amongst klal yisroel but Saducess and Baytosim that deny this acceptance in every facet and doubt that which is written in the Torah and their thinking is not from this group but from the group that say there is no Torah from heaven like we explained in Chapter 10 of this tractate. When they deny the fundamentals/foundations of Torah, they are put to death due to their heresy like we put to death one who denies G-d, or one who denies (the existence of) Moshe Rabbeinu. Since all those who destroy the foundation from these foundations that I said to you leaves the category of a 'baal Torah' (i.e. owner of Torah). However, I have already been at length with this matter and all who uproot this belief no-one should be provoked by them.

So if I have understood this Rambam correctly, Tzaddok and Baytos were not deserving of death due to zekeinim mamrim but rather purely for acting out of kefirah.

In addition, we see from the Rambam that it only becomes an issue if people 'complete' the act of heresy i.e. translating their warped logic into action. The Ikkar Tosafos Yom Tov writing on the Bartenura to Pirkei Avos 1:11 notes:

And Rashbam wrote in the name of Avot DeRabbi Natan that Tsadok and Beitos were teaching their students the words of Antigonos and the students erred.

Answer 2

Rambam directly addresses this in Chapter Three of Hilchot Mamrim:

מי שאינו מודה בתורה שבעל פה אינו זקן ממרא האמור בתורה אלא הרי זה בכלל האפיקורוסין [ומיתתו בכל אדם] מאחר שנתפרסם שהוא כופר בתורה שבעל פה [מורידין אותו] ולא מעלין והרי הוא כשאר כל האפיקורוסין והאומרין אין תורה מן השמים והמוסרין והמומרין שכל אלו אינם בכלל ישראל ואין צריך לא לעדים ולא התראה ולא דיינים [אלא כל ההורג אחד מהן עשה מצוה גדולה והסיר המכשול] במה דברים אמורים באיש שכפר בתורה שבעל פה במחשבתו ובדברים שנראו לו והלך אחר דעתו הקלה ואחר שרירות לבו וכופר בתורה שבעל פה תחילה כצדוק ובייתוס וכן כל התועים אחריו אבל בני התועים האלה ובני בניהם שהדיחו אותם אבותם ונולדו בין הקראים וגדלו אותם על דעתם הרי הוא כתינוק שנשבה ביניהם וגדלוהו ואינו זריז לאחוז בדרכי המצות שהרי הוא כאנוס ואע״פ ששמע אח״כ [שהוא יהודי וראה היהודים ודתם הרי הוא כאנוס שהרי גדלוהו על טעותם] כך אלו שאמרנו האוחזים בדרכי אבותם הקראים שטעו לפיכך ראוי להחזירן בתשובה ולמשכם בדברי שלום עד שיחזרו לאיתן התורה אבל זקן ממרא האמור בתורה הוא חכם אחד מחכמי ישראל שיש בידו קבלה ודן ומורה בדברי תורה כמו שידונו ויורו כל חכמי ישראל שבאת לו מחלוקת בדין מן הדינים עם בית דין הגדולולא חזר לדבריהם אלא חלק עליהם והורה לעשות שלא כהוראתן גזרה עליו תורה מיתה ומתודה ויש לו חלק לעולם הבא, אף על פי שהוא דן והן דנים הוא קבל והם קבלו הרי התורה חלקה להם כבוד ואם רצו בית דין למחול על כבודן ולהניחו אינן יכולין כדי שלא ירבו מחלוקת בישראל

A person who does not acknowledge validity of the Oral Law is not the rebellious elder mentioned in the Torah. Instead, he is one of the heretics and he should be put to death by any person.

Since it has become known that such a person denies the Oral Law, he may be pushed into a pit and may not be helped out. He is like all the rest of the heretics who say that the Torah is not Divine in origin, those who inform on their fellow Jews, and the apostates. All of these are not considered as members of the Jewish people. There is no need for witnesses, a warning, or judges for them to be executed. Instead, whoever kills them performs a great mitzvah and removes an obstacle from people at large.

To whom does the above apply? To a person who denied the Oral Law consciously, according to his perception of things. He follows after his frivolous thoughts and his capricious heart and denies the Oral Law first, as did Tzadok and Beitus and those who erred in following them.

The children of these errant people and their grandchildren whose parents led them away and they were born among these Karaities and raised according to their conception, they are considered as a children captured and raised by them. Such a child may not be eager to follow the path of mitzvot, for it is as if he was compelled not to. Even if later, he hears that he is Jewish and saw Jews and their faith, he is still considered as one who was compelled against observance, for he was raised according to their mistaken path. This applies to those who we mentioned who follow the erroneous Karaite path of their ancestors. Therefore it is appropriate to motivate them to repent and draw them to the power of the Torah with words of peace.

The "rebellious elder" mentioned in the Torah, by contrast, is one of the sages of Israel who has received the tradition from previous sages and who analyzes and issues ruling with regard to the words of Torah as do all the sages of Israel. His rebellion involves an instance when he has a difference of opinion in one of the Torah's laws with the Supreme Sanhedrin and did not accept their views, but instead issued a ruling to act in a different manner. The Torah decreed that he should be executed. He should confess his sin before being executed so that he will be granted a portion in the world to come.

Even though he analyzes and they analyze; he received the tradition and they received the tradition, the Torah granted them deference. Even if the court desires to forgo their honor and allow him to live, they are not allowed so that differences of opinion will not arise within Israel.

(Touger translation)