Now I suppose the question of whether or not this show is "smart" is dependent upon one question: is this show a biting criticism of the justice system or is it to be taken at face value? Unfortunately given the tendency of the show to have defense attorneys who are the embodiement of evil, as well as the fact that an unusually high statistic of the suspects in complex murder cases are guilty makes me lean towards the latter. While I normally have no issue with those things in corny shows like "Castle" I do take issue with it in a show that trys to be "realistic".
The cops are judgemental jerkasses, but they could be considered good. Kind of. Again it's hard to tell whether their somewhat absurd social conservatism (such as detectives being disgusted by victims who were into BDSM or not achknowledging the existence of bisexuals when it could change the circumstances of a case, or a lackluster care of sex workers who are victims of violence) or their willing to intimidate people is meant to be a critique of such attitudes in law enforcement or intended to make them look like the only sane men in a decadent world. I suppose it's possible it's just trying to make them more morally grey but I really think the show is basically urging us to agree with them.
Far worse, however, is the DA. The attorneys appear to only care about getting a conviction, no matter what. They seem to barely put any thought into whether or not the victim is guilt. In one episode Mc Coy
literally says "I don't care why she got convicted, just that she did". It's informed likablity and Designated Hero
taken to the extreme. Again it's genuinly hard to tell whether we're suppose to root for them half the time, they are presented as always being right and basically combating a mad world. However face it if you were on trial and were innocent you would not want these lawyers trying to convict you. While NCIS is criticised for having mean characters Law and Order seems like a far worse case of this.
In short if this show is a critique of real life law and order it's pretty thoughtful (if depressing). But I don't think it's that thoughtful. It pushes us to agree with charactars who are callous ruthless bullies who are only "good" because somehow EVERYONE they catch happens to be guilty despite that being statistically impossible.