Gemara

(Rava of Parzakya): Many people frequent a Mavoy. No one person is responsible. Everyone relies on the others. (Perhaps the part of the Korah below 20 will be removed, and no one will notice!)

This is like people say, that a pot of partners is neither hot nor cold.

Bava Basra 24b (Mishnah): We distance a tree 25 Amos from a city;

If the city was there first, we (people of the city) may cut it without paying the owner;

If the tree was there first, we may cut it, but we must pay.

If we are unsure which came first, we may cut it, and we need not pay.

Question: Why can't the owner demand to be paid before they cut the tree?

Answer (Rav Kahana): A pot of partners is neither hot nor cold;

i. If we are unsure which came first, in any case the tree should be cut. We are in doubt if we must pay for it. To collect money, the owner must bring proof.

Question: Why is this different than a tree near a pit? (There, he may not cut due to Safek!)

Answer: There, if the tree preceded the pit, it should not be cut. When in doubt, we do not cut.

55a (Rav Huna brei d'Rav Yehoshua): Even if land was sold for the [owner's] head tax, the sale is valid. The tax creates a lien even on Peros in a Kli!

Question (Ameimar): If so, a firstborn does not get a double portion, for the father was not Muchzak in his land. Whoever paid the tax would receive it!

Answer (Rav Ashi): Indeed, he gets a double portion only if the father already paid the tax.

100a (Beraisa - R. Yehudah citing R. Eliezer): If the public chose a path [in Reuven's property], they keep it.

Question: Are the public robbers?!

Answer (Rav Gidal): The case is, they had a path in Reuven's land, and it was lost.

Bava Kama 27b (Rav Yehudah): One may not take the law into his own hands;

(Rav Nachman): One may.

All permit when needed to avoid a loss. They argue about when there is no loss. Rav Yehudah forbids, for he can go to Beis Din. Rav Nachman permits.

Bava Metzi'a 73b - Question (Ravina): There are people who pay the tax for abandoned land and grow grapes on it. Is the wine forbidden because the land was stolen?

Answer (Rav Ashi): No. The taxes are in the king's treasury. He says that whoever pays the land tax, he gets the Peros.

Mo'ed Katan 17a: A Chacham may take the law into his own hands if he knows that this is the Halachah.

Rishonim

Teshuvas ha'Rosh (6:26): If something is known to the Rabim, or to the city governors, they may take from one who was Machazik. They do not need Beis Din or witnesses. We learn from Mo'ed Katan 17a. Rashi explains that if he knows the law, he may take from the one who owes him b'Al Korcho (against his will), and he may excommunicate him for not paying. All the more so, if the law is clear to most of the city or the city governors, they may take b'Al Korcho.

Maharik (1): Surely, people of a city cannot force someone not of their city to come to their city for judgment. Even R. Ami and R. Asi could not enact something like this, which benefits one and harms another.

Maharik (2): One who flees from a city does not lose the law of an individual who has a Din with the Tzibur. The Mordechai at the end of Bava Basra Perek 2 that the Rabim are Muchzakim. If a tree grew before a city was built, first they cut it, and afterwards they pay. Failure to pay taxes is like damage. The city is considered [Muchzak, and the] Nitva (the one from whom the claimant wants to collect), and the individual is the Tove'a (claimant).

Maharik (3): Even if the city was not Muchzak, when they have a Din against individuals, they are considered Muchzakim.

Mordechai (Bava Basra 522): The custom is that if an individual has a Din with the Tzibur about taxes, the Tzibur is Muchzak. First they collect, and then they have the Din. The Tzibur wants to be Muchzakim and Nitva'im. If not, there would be no solution. Everyone would do improperly, thinking that no one will claim from him, for a pot of partners is neither hot nor cold. Our Gemara supports the custom. In many places that Chachamim were concerned for a loss to the Rabim. If the Rabim were Muchzak to use a path, one may not ruin it. Maharam brought a proof from Bava Metzi'a 73b. Rav Sheshes said 'their signet rests in the king's chest...' These words show that the king is Muchzak in everyone's tax. Whenever there is a Safek or unclear claim to be exempt from tax, one is liable until he proves otherwise. If the city has a custom, we follow it.

Terumas ha'Deshen (341): The custom is that a Rabim against individuals are considered Muchzakim. The Mordechai supported this from Maharam. If an oath applies, the Tzibur may take the oath, or reverse it on the individual. They always have the upper hand. The city may cut a tree, and the owner must bring a proof in order to collect. The Gemara asked why this is different than a tree near an individual's pit. A marginal note in Tosfos says that the Gemara could have answered that Rabim are unlike an individual. This proves that the Rabim are considered Muchzak against an individual in every Safek, even not about taxes. However, this is unlike Maharam. The Mordechai said that Maharam considers the Tzibur Muchzak only regarding taxes. It seems that the same applies to everything the government collects. We do not say so for other needs, even though the reasoning 'a pot of partners is neither hot nor cold' applies. It helps only to take a security, in order that the individual will avidly pursue the Din [to get back his security]. They are not Muchzak to say 'I am sure that the Halachah follows this Gaon' or to reverse oaths. If a Sefer Torah was stolen, some say that two people of the city may forfeit their rights to it, and then testify about it. Maharam said that we do not rely on this. However, if the individual is a Chacham whose sole occupation is Torah, the Rabim are not Muchzakim against him. We do not impose taxes on a Chacham, since he does not need to be guarded. Also, we are not concerned lest he harm the Rabim out of confidence that no one will claim against him. This applies to anyone established to be a Chacham in his generation.

Tosfos (55a DH Im): We do not say that a firstborn does not get double when there is a Kesuvah or a loan with a lien against his father's property. The creditor or wife did not collect yet. There is a lien on all land for the king's tax. The king is Muchzak in the land. He need not collect it.

i. Rashbam (100a DH keshe'Avdah): We know that the Rabim had a path. They have greater rights than an individual. If Ploni lost a path in Almoni's property, he may not choose a path. Beis Din or Almoni decide what he gets. Rabim are like Beis Din. Which of them can one summons to Din?!

Poskim

Shulchan Aruch (CM 4:1): One may take the law into his own hands... if he can prove that he acts according to Halachah.

Rema: All this applies to an individual against an individual. If an individual opposes a Rabim, if he is from their city, they may carry out the law themselves.

SMA (5): The Rema said that he is from the city, like Maharik (1). Really, he need not be from the city. It suffices that he pays taxes to the same governor. Darchei Moshe (3 DH Kasav) concluded like Maharik wrote in Shoresh 2, that it is even if he is not from the city. With difficulty, we can resolve the contradiction. Here, the Rema did not discuss someone from another city, for he was unsure about the law.

Rebuttal (Shach 9 and Gra 17): Maharik (1) requires that he be from the city only for the Rabim to take the law into their own hands. In Shoresh 2 he says that the Rabim are Muchzakim against an individual even if he is not from their city. This is the Rema's intent.

Gra (16): We learn from Mo'ed Katan 17a. The Rabim have the law of a Chacham, like we said above, that a pot of partners is neither hot nor cold. (Likut) A Chacham may take the law into his own hands, even though he cannot clarify the matter [to others], because he is busy with his learning [and cannot take time from it]. The people of the city may do similarly [even if they cannot clarify the matter]. Bava Basra 100a and the Rashbam there say so.

Nesivos ha'Mishpat (4): Against people of their city, the Rabim may take the law into his own hands even when an individual could not, e.g. he has no claim on the money itself. We learn from the law of a Chacham (Mo'ed Katan 17a). Surely they may seize, in order to go to Din.

Rema (ibid.): If they have claims against each other, the Tzibur is Muchzak against the individual.

Beis Yosef (DH Tefisah): Maharik (2) says that the Tzibur are Muchzakim and they are the claimants, and not the Nitva'im.

Shach (10): Only regarding taxes, the Rabim are Muchzakim to be able to say 'we are sure that the Halachah follows Ploni.'

Rema (ibid.): He must give to them a security before they have the Din with him. They are Muchzakim only regarding taxes, but not for other matters. In any case he must give a security before the Din. Neither of these applies if the individual is a Chacham whose sole occupation is Torah

Gra (20): We learn [that they are Muchzakim only regarding taxes] from the difference between [a tree near] a pit [and a tree near a city]