There are, in fact many ways in which law and history intersect. There is, for example, an entire branch of history that looks at the development of law as a set of ideas and of practices (both statutory and judicial) with widespread social effects. My own research, on public international arbitration and on certain forms of imperial treaties, focuses on this field.
However, my colleague’s question got me thinking about how law (in the particular mode of litigation and judicial decisions) uses history and historical forms and practices. Lawyers will tell you that they deal with two things in each case: the “Law” and the “Facts.” In a sense, each judicial decision describes the intersection of two stories, i.e., two histories: one is a story/history of the law and the other is a story/history of the facts. Actually, given the complexities of life and of the legal process, there are always multiple stories in each category: different pieces of the law are brought into consideration in each case and there are usually multiple sets of facts (not least of which are the “substantive” facts (e.g., which car ran into the other, who said what in a business negotiation) and the “procedural” facts (e.g., who filed suit, against whom, in what court, using what theory, etc.)).
Lawyers, in arguing their case, and judges, in their opinion, each construct each type of story; that is, they’re writing history. Yet, while they’re all trained as lawyers, only a few are trained as historians. Having run the gauntlet in each discipline, I can tell you that they are not the same thing at all.
Take, for example, the idea of “legislative history,” i.e. the idea of looking at the debates and information considered by the law maker (e.g. Congress) as it was adopting a particular statute as a means of figuring out how to interpret that statute. It’s a highly constrained mode of history. Legal parameters about written documentation and official records ensure that judges consider only a subset of the motivations and understandings of law-makers. Was a niece of a House committee chair diagnosed with an ailment a few months before legislation was enacted to add that ailment to Medicare coverage? Highly relevant, to be sure, certainly a factor that a regular historian would consider; but nowhere to be seen in the “legislative history.” Then there is the problem of parsing out who thought what in the course of a legislative process that involved hundreds of people. Whose perceptions and statements count for more than others? What did they really think? These imponderables are part of why “constitutional originalism” (one variety of “legislative history”) is particularly fraught as a method of interpretation. So, this makes for good interpretive law-making (of the judicial variety), but it’s nothing a historian would sign on to. That’s part of the reason most historians think that constitutional originalism is bunk. Indeed, most “historical assessments of legislation are broad in their consideration of different factors and generally avoid relying on particular causative chains since getting into people’s heads is a dicey historical proposition.
On the other hand, if we accept that history is (in the words of E.H. Carr) “a dialogue between the past and the present,” then we can see that the legal principle of precedent (i.e., sticking with past decisions unless there is a clear and articulatable change of circumstances) seems to fit the historical bill. Negligence principles, for example, date back hundreds of years in the Anglo-American legal system. They hadn’t seen the need to create “no left turn” lanes for cows in 14C England; but by the turn of the 20C, when motorized vehicles appeared on the scene, there were no explicit rules about their proper operation and liability for accidents. Courts adapted traditional principles to the new set of circumstances. This required extracting the essence of the jurisprudential idea and distinguishing the old set of facts from the current circumstances; precisely what historians do…in a sense. But, it’s pretty rare to see court decisions thoroughly analyze the historical context of the decision they’re citing as precedent. The law (and judges and lawyers) can do this because their focus is on the principles, not on the historical facts. Instead, precedent exists as a stack of rules/principles which need interpretation in the present day. The articulation of difference in order to justify a new result (i.e. an updated principle) is what judges do. By comparison, historians—while we articulate difference over time as well—are interested in the historical facts and not (if we’re being good historians) in judging current events.
A trial, on the other hand, is about producing a coherent story of what happened; as is an historian’s analysis. Of course, neither the judicial trial nor historians’ processes should be confused with determining the “truth” of a situation. Both have limits; and both acknowledge their limits, but there are some shared and some different constraints. For example, the “hearsay” rule or the 4A exclusion of improperly seized contraband both ignore pieces of evidence (i.e., create gaps in the stories being constructed) that historians love to chew over. Both require footnotes (although sometimes for different purposes) and lawyers require chain of custody of incriminating evidence. Both work with sources of limited reliability: memory, bias, and gaps. Both try to get at this “truth” thing, both know they will fail, and both are surprisingly comfortable with that failure. For lawyers, the priority is the immediate case and the client. For historians, the priority is the process of increasingly approximating the truth over time and (or should be) the honing of minds and souls.