Most law professors have a JD. Often, the JD robe for a school is different. One easy example: Harvard JDs wear a black robe at graduation instead of the crimson robe. At Yale, the JD robe is black but the Ph.D robe is blue.
Yet, many Harvard JDs who become law professors wear the traditional Harvard crimson doctoral robe. Is this okay?
I think at many schools, the JD robe is different (black often with purple stripes on sleeve). At some schools, the JD robe is the same as the Ph.D. robe (Cornell, USC). So which is it if you are a law professor and want to wear a robe from your JD school?