In law schools do JD professors supervise PhD students? I know that law schools, unlike most other academic faculties hire a significant portion of their professors without a doctorate (PhD, D.Phil, etc) but just with a JD law degree.
I come from a science background so this notion is pretty foreign to me.
Do the JD professors supervise doctoral and/or master's students? I know that these professors will still engage in legal scolarship/ publishing papers but it would seem inappropriate for them to be issuing doctorates if they themselves don't have one.
I am an academic in a different field but my spouse is a (tenured and endowed-research-chair holding) law professor without a Ph.D. They supervise doctoral students with no issues.

The Ph.D. is a marker, a rite-of-passage that the young academic has made their initial significant novel contribution to the corpus of knowledge, and has learned enough tradecraft to be standalone researcher. While a Ph.D. is a big deal when you're getting one and when you've just received one, it is but a first instance of what a research academic does over and over again for the rest of their academic career. So a mid-career (or later) research-focused academic has loads of experience in &quot;Ph.D.-level&quot; research, whether or not they actually obtained that degree at the start of their careers. And a teaching- and/or service-prioritizing professor who does fairly little research has pretty limited relevant experience irrespective of whether they actually did an actual Ph.D. way back when.

As @astronat wrote in the comments, the Ph.D. is actually awarded by the university, on the recommendation of the department, and on the basis of the evaluation by the whole dissertation committee. So to the extent the issue is whether a non-Ph.D. can judge the specific level of achievement (etc) warranting the Ph.D., if there is any uncertainty at all, the broader set of voices involved will provide additional feedback. As you can imagine, my spouse found this useful as a sanity check the first few times they were supervising without themselves having the specific degree, but this became less relevant over time.


Bottom line is the same criteria for what makes a good supervisor apply as in other fields (research proficiency, care for students, time to advise, well-connected to help find students jobs, etc.) and the Ph.D. credential is just less important in fields (like law) where historically this credential has been less commonplace.