With the episodes from 'Law and Order's' middle period and from its later seasons airing so often, it is very easy perhaps to overlook the early seasons. Meaning in my view pre-Season 7. That is a shame, because 'Law and Order' in its early years was more often than not good to fantastic with some truly fine episodes in each of the seasons in question. Even if there were a few not that major bumps along the way and times where it didn't always feel settled, Season 2 for example took some of its first half to completely settle.
"Promises to Keep" is one of the fantastic episodes. It is one of the best of Season 3 and an early season standout in its own way. There are many episodes that show perfectly what 'Law and Order' is all about as a show and "Promises to Keep" is one of them, if anybody got into the show via the later seasons (admittedly me being one) and hasn't seen any of the pre-Season 7 episodes yet should really do so and this is a strong example as to why. Everything here works.
It is a must for two things especially. One is the chillingly cunning performance of Lindsay Crouse in one of her better performances perhaps. The other is the powerful, quite the knockout scene between Meade and Olivet (played beautifully by Carolyn McMormick and they contrast just as beautifully).
They are not the only good things though. As said, everything in "Promises to Keep" is good. While Crouse gives the best performance, Jerry Orbach and Michael Moriarty are also excellent in their roles as one would expect. The character chemistry is right on too, especially between Meade and Olivet in that aforementioned scene. It's slickly shot with nice use of locations while the music is wisely not constant and is unobtrusive.
Furthermore, the script is thoughtful and tonally expertly balanced, whether it's the taut legal scenes, some of the tense interaction in the legal scenes between the regulars and Briscoe's one-liners. There are moments of unsettlement, like with Meade's matter of factness on the stand but it's balanced by moments of amusement from Briscoe and Schiff. The story is riveting, it's never too simple or convoluted and has tension and unpredictability too. The first half where we see how the conclusions are gotten to intrigues but the second half is even better, with more tension.
Overall, fantastic. 10/10