You know what? Screw the way lawyers use words. I mean, fawk! I ran into this the other day: "The election may be made with or without traverse." I managed to figure out what they meant using google, but why do they write like this? With the way word use changes over time in addition to the screwy way lawyers use words, trying to interpret what was meant when a word was written or what it means according to today's use is no simple thing.
There are a lot of reasons why.
In law school (law school blows, BTW, but that's another story) they said don't do this; just write in plain English to the extent possible. They said when lawyers use Latin, archaic "Law French" or out-of-date terms, they're just doing it to appear sophisticated and justify their status and superiority on legal matters... i.e. to impress clients and justify their hourly rate.
to be fair though, there are some objective reasons to use latin/law french, like where the phrase is readily understood by lawyers and judges (or at least most of them), AND it's shorter than plain English. Helps get around character or page limits courts may impose on briefs, and reads easier
example:
saying "inter alia" is shorter than "among other things"
Sometimes a latin phrase is so well understood and accepted in legal doctrine that you might screw up by NOT using it, like "mens rea" or "res ipsa loquitur."
the way to cite cases and references in formal briefs or law review articles is also codified, and includes a number of latin terms: supra, infra, id., contra, etc. if you try to do citations your own way, important legal people will throw your writing right in the trash without reading it
Judges can usually just do whatever they want though, since they are in charge. most judges try to write straightforward opinions, knowing their work product is for the public good and will be studied by future lawyers and legislators when they provide counsel or make policy.
but Scalia was pretty notorious for including archaic or obscure words and phrases to "appear smart." In his case, that was probably important... it's important to at least "appear smart" and give your shit opinions a high polish when you're just there to deliver for GOP donors, without regard to concerns over setting bad precedent.