n Drives Jewish Law on Women
and Hawaii) with a clear chain of legal authority, nevertheless is subject to modification and even to veto by popular custom.
As a result, one must come to understand that the content of the law itself is always a product of the interaction between the dictates of those entrusted with interpreting and applying the law and the actual practices of those governed by it. Law and custom, din and minhag, may pull in opposite directions, but they ultimately must take account of one another because neither automatically supersedes the other. In the paragraphs below I will use American law to illustrate these multifaceted interactions so it is clear that custom has authority of its own and affects law even in fully functional and enforced legal systems.
Sometimes law overrules customs or creates new ones. In
American law, one example of that process was Brown v. Board of Education(1954) and the subsequent Civil Rights Act of 1964 . That Supreme Court decision and Congressional legislation not only changed many state laws and local ordinances, but also changed some of the social and commercial customs based on Segregation . So, for example, before that time advertisements almost never depicted blacks and whites enjoying a given product together, but by the 1960s such pictures began to appear. On the other hand, custom can undermine law and change it. The clearest example in American law is Prohibition. Most Americans —probably some eighty-five or ninety percent— abided by the law, but the refusal of the remainder to do so made Itimpossible to enforce even a law with the status of a constitutional amendment.
Conversely, custom can be the source of new laws. One clear ®ample in American law is the Uniform Commercial Code , a Version of that forty-nine states ultimately passed. This code Specifically invokes the“usage of trade” as a criterion for judging cases.' A parallel development in Jewish law is the case of wine Merchants putting their marker on kegs of wine, which, according to the Talmud , does not normally effect a legal transfer inyan), but it does do so if that is the custom among merchants.!”
Periodically, every legal system has to catch up to the actual Practices of the people it seeks to govern. Sometimes, as we have Seen, the legal authorities will seek to uproot a custom that has *Merged, and sometimes they will instead confirm it in law.