Season 7 started off very, very well with "Causa Mortis". Not as brilliant as 'Criminal Intent' with "Amends", but a lot better than 'Special Victims Unit' with "Demons". The plot synopsis really does sound fascinating on paper and suitably complex (not a problem, 'Law and Order' often did complexity very well indeed) and Jamie Ross (only introduced in the previous episode and showed a lot of promise in it) to me was always one of McCoy's better partners.
"I. D." is as fascinating and as intricate as it sounds. It continues the high standard set by "Causa Mortis" and manages to build upon it and be an even better episode. Season 7 was solid on the whole, and "I. D." is one of the standouts when it comes to talking about Season 7's best episodes. As has been said, it is two stories in one structurally which faces the problem of being disjointed and the quality not being equal. Both problems are successfully avoided.
Can't think of anything to fault "I. D." for. It is shot with the right amount of intimacy without being claustrophobic and that the editing has become increasingly tighter over-time has been great too. Nice use of locations too. The music doesn't get over-scored or overwrought, even in the more dramatic revelation moments. The direction doesn't try to do too much and is understated but never flat or unsure. The writing is intelligent and although, like the show in general, there is a lot of talk it doesn't feel long-winded. Marks' dialogue is as juicy as the juiciest of peaches, is witty and is very high up on the skin crawl factor.
Both the investigating and legal subplots are brilliantly done and it doesn't feel to me too much like two stories in one, instead two different subplots that connect together. Although it's the legal story that is always mentioned whenever "I. D." is discussed for good reason, one shouldn't overlook the case. Which is an incredibly clever and intricate one, and that there is much more to the perpetrator than what it initially seems has the definite shock factor. The truth was so unexpected on my first watch, didn't even consider it as a possibility until it was revealed.
The case does deserve to be discussed more but it is easy to overlook it with the legal/harrassment subplot being so juicy. Thanks to the unforgettable character of Marks, one of the most memorable judges in the franchise with a larger than life creepiness and contempt without unbalancing everything else. A favourite scene of mine from the episode is when McCoy introduces Schiff to his cellmates when in contempt. The ending is one of the stand up and cheer in complete satisfaction ones.
Performances are excellent all round, with Jerry Adler standing out as Marks. He was very clearly enjoying himself without veering into pantomime. Pamela Grey brings out many dimensions to her role, one of those performances that brilliantly makes one feel at first sympathy for the character but revile her by the end.
Overall, brilliant and a Season 7 standout. 10/10.