The Law of the Land is not Always the Law

R`Joshua, son of Karchah, sent word to him, 'Vinegar, son of wine! How long will you deliver up the people of our God for slaughter!'

[R' Eleazar] sent back the reply: 'I weed out thorns from the vineyard.'

R`Joshua sent back the reply: 'Let the owner of the vineyard [God] come and weed out the thorns.'

One day a laundryman met him, and called him: 'Vinegar, son of wine.'

Said the Rabbi to himself, 'Since he is so insolent, deduce from it that he is certainly a culprit.'

So he gave the order to his attendant: 'Arrest him! Arrest him!' When his anger cooled, he went after him in order to secure his release, but did not succeed.

Thereupon he applied to him, the verse, "One who guards his mouth and his tongue, guards his soul from troubles (Prov. 21:23)

Then they hanged him, and [R`Eleazar] stood under the gallows and wept.

Said [his disciples] to him: 'Master, do not grieve; for he and his son seduced a betrothed maiden on Yom Kippur.'

[On hearing this,] he laid his hand upon his innards and exclaimed: 'Rejoice, my innards! If matters on which you are doubtful are such, how much more so those on which you art certain! I am well assured that neither worms nor decay will have power over you.'

In spite of this, his conscience disquieted him.

One may vow [in front of] murderers and thieves and [royal] tax collectors that [something] is terumah, even if it isn't terumah

The general principle is: Any law that a king decrees to be universally applicable, and not merely applying to one person, is not considered robbery. But whenever he takes from one person alone in a manner that does not conform to a known law, but rather seizes the property from the person arbitrarily, it is considered to be robbery.
Therefore, when the king's tax collectors and enforcement officers sell fields because the owner did not pay the fixed tax for the field, the sale is binding. A head tax, however, is the personal responsibility of each person and it may not be collected from his property. Thus, if a field was sold because an individual was delinquent in paying the head tax, the sale is not binding, unless this is the law enacted by this particular king.

if a king decrees that whoever pays a head tax for a person who has not paid acquires the delinquent person as a servant the decree is binding. If one Jew comes and pays a head tax for another indigent, he may compel him to work beyond ordinary limits, for the laws of a king are binding. He may not, however, have him toil as a slave.

Gloss (from the Mappah): ...If a (man) marries a woman in a place in which rulings are (made) in the courts of non-Jews and his wife died, the father of his wife or the rest of her successors could not (claim the inheritance), which is to say, any man who marries a woman, who gets married under (non-Jewish) custom, and the matter is ruled through non-Jewish courts that if she died, her husband inherits it or something along these lines, there is no grounds to apply the concept of "the law of the land is the law," for we only apply "the law of the land is the law" in a matter that involves benefit for the king, or that is for a legal change for the members of the state, but not in the cases where non-Jewish courts make rulings, for if this were so, they would have nullified all the laws of Israel.