I have a legal system that uses blood relatives as legal unit. For example Joe owes 120K in unpaid parking fees. The court auctions his property but that only fetches 20K. Under the same jurisdiction there are 4 of Joe's relatives: his grandfather, his sister, his first cousin and his second cousin. Genetic similarity for each is (grandfather 25%, sister 50%, 1st cousin 12.5%, 2nd cousin 3.13%) or in total 90.63.

The court orders them to pay following amounts, from their property.

  • Grandfather 25/90.63 = 27.5K
  • Sister 50 / 90.63 = 55.1K
  • 1st Cousin 12.5 / 90.63 = 13.8K
  • 2nd Cousin 3.13 / 90.63 = 3.4K

If any of the relatives can't pay the full sum, the court will auction their property, if that is still not enough, the relative is considered bankrupt and released from the rest of the debt i.e. the debt doesn't cascade.

If the punishment is imprisonment, the relatives will have to do time proportionally, if instead of going to jail, Joe decides to skip town. If the punishment is death, it will be considered the same as 100 years of jail.

How would family relationships be affected?

Is there anything similar in history?

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    $\begingroup$ Spreading jail sentences over the relatives is a totally absurd idea. That system would collapse in years. Practised blood vengeance is and has ever been an open sign for a failing society. Civil financial liability as a family is however even today practised in modern states, although not as archaic as you describe it. $\endgroup$
    – Karl
    Oct 1, 2016 at 21:18
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    $\begingroup$ clan of 100 people can easily kill any person, just 1 year of sentence for each member, nice. vote for that, will solve lot of problems. $\endgroup$
    – MolbOrg
    Oct 1, 2016 at 22:41
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    $\begingroup$ Man, I'd love to be a lawyer in that world. They say that, in a civil suit, you go after the deep pockets. By your system everyone has deep pockets. This could be the single most litigious society ever created! $\endgroup$
    – Cort Ammon
    Oct 1, 2016 at 23:05
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    $\begingroup$ What makes your variation interesting is that it depends on closeness of ties. So where the family starts and ends is different for everybody. This is quite different from the traditional approach where you have clear family boundaries and everybody within a family has the same head-of-family. $\endgroup$ Oct 2, 2016 at 8:33
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    $\begingroup$ Isn't this just north-korea, except that they also put in jail future members of the family? $\endgroup$
    – Bakuriu
    Oct 2, 2016 at 10:16

5 Answers 5


If the punishments only spread in failure cases (that is, in the case that Joe commits a crime, is successfully caught, and serves his own sentence his relatives aren't punished at all), then there's a strong incentive for family members to hire bounty hunters, or track people down themselves to make sure they serve their terms. -- You can practically guarantee that the family matriarch/patriarch will keep track of intimate details about where you live, where you have your money stored, who you associate with, any locations you're familiar with, etc. Basically, anything which will help track you down in case you go on the lam. You wouldn't have any privacy from family members, and there probably would be laws which support that.

As the penalties also extend to financial responsibility, the legal concept of a lien (or related) would probably also be extended. That is to say, your relatives would be able to place restrictions on your financial dealings. Want to take out a loan? The bank needs to run it by your aunts and uncles first. -- This would probably put a damper on third-party loans, instead resulting in a system where everyone pays cash up front, or, if they get a loan, it's explicitly through family members, and you're limited in the loan amount based on how much they have.

"Black Sheep Insurance" would probably also be a thing. Have a fiscally irresponsible relative? Take out an insurance policy against your relative, which promises to pay if they default. This would play into the extension of liens - now the insurance company can limit how much money you spend and which loans you can take out.

SRM mentions marriages, but what happens with adoptions is also interesting. Unless there's a legal framework to sever blood ties in the case of adoption, I'm guessing stranger adoption would just not happen. There's no way you'd permit someone who can put you into legal liability to be raised by a (potentially irresponsible) third party. Adoptions might happen, but they'd be limited to close family - by grandparents, aunts & uncles, brothers & sisters, etc.


Why would family structure changing matter? I can't declare my sibling "not my sibling", especially if the law recognizes genetic similarity. You're stuck with the family you're dealt with. But fratricide might be common to avoid a deadbeat draining a family. It might even be enshrined in law to allow a parent to kill off a child that is too rebellious.

Now what would change is marriage. I guarantee that family would have a FAR greater say in blocking a wedding. Since grandparents are on the hook, out-of-wedlock births would be a huge deal, possibly with grandparents on either side having the right to demand an abortion (if the liability only stretches to parents for bastard kids, that would make more sense to me).

Paternity testing had better be a science or else the law needs to settle claims of paternity quickly and permanently soon after the child is born.

Since your system only extends one level out, I don't think there's any forcing of clan relationships. If the punishment kept spreading, you might have clan patriarchs/matriarchs strongly monitoring everyone.

You might have reduced birth rates to limit liability risk. Or you might have accelerated birth rates to limit liability exposure. I can make a case either way.

  • $\begingroup$ What do you mean by it only spreads only one level deep? All your blood relatives are liable if they live in the same jurisdiction, it's the debt of the relatives that doesn't cascade. $\endgroup$
    – Chonin
    Oct 1, 2016 at 20:58
  • $\begingroup$ I meant it doesn't jump across marriages. Your spouse is immune, and your spouse's family. $\endgroup$
    – SRM
    Oct 1, 2016 at 22:15
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    $\begingroup$ The legal complications of fratricide could be interesting. Cain attempts to kill his brother Abel, but is unsuccessful. He's tried and convicted of the attempted murder, but skips town. This means his relatives are on the hook - so does that mean Abel has to serve time for his own attempted murder? $\endgroup$
    – R.M.
    Oct 1, 2016 at 22:30
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    $\begingroup$ Interesting. Seems like crime against a blood relative would not be a crime. Theft, murder -- if legally you're all the same person, there's no harm committed if it is done within the family. $\endgroup$
    – SRM
    Oct 1, 2016 at 22:33

"Was there anything similar in the history?"

Actually yes - the first law that fully recognized individual (and not collective responsibility) was Mosaic Law, before that it was mostly collective responsibility. (under Hammurabi code, if house collapsed because of shoddy work and killed the son of head of family, then the son of builder would face punishment of stoning). In not so far away times, in the Soviet Union if one escaped to the West, his family could have been imprisoned, technically for not preventing that.


Under such law large extended families that are socially cohesive have huge advantage over individuals and nuclear families. So I expect the society to be dominated by clans and extended families, and I expect huge amount of inbreeding unless there's some mechanism to counter it. If my brother that I don't get along with steals lot of money, it will devastate me too. However large clan that could keep their members in check might weather even relatively large storm. I think society will tend to many children, but it will ruthless to rebellious individuals. Being the black sheep of the family could easily get you killed by your relatives, who don't look kind to going in jail just because you want to fight against some powerful politician. So expect a lot of nepotism, collectivism and cousin marriages.

The Paradox of Modern Individualism

Why cousin marriage matters in Iraq

Nepotism as moral duty


Ancient Romans used a similar system and it is well documented. Paterfamilias was liable for torts his family (including slaves) committed, but in exchange had the power of magistrate over them. His dependents had a very limited legal existence and e.g. could not own property in their own name or sign contracts. A man's wife, if married in strict form, was technically adopted by his family and had a legal standing similar to his sister (if his father was paterfamilias) or daughter if he was paterfamilias; this is where terms like "father-in-law" come from. Much later, the Normans revived part of this system as coverture marriage, and some of its relics still survive in modern law, e.g. the reason a wife could not testify in her husband's case was that she had no separate legal standing in court.

In your case, if you put such heavy responsibility on family members without giving them commensurate powers, it will put too much strain on the family system. Either people will stop having families, or they will find extra-legal ways to exercise the powers necessary to keep families viable.


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