This program was originally made for HBO. It has a lot of swearing, a lot of graphic violence and a lot of nudity. With the exception of the swearing, however, it is not as gratuitous as some of the other original programming they have in the 'look, we're on cable and we can do this stuff' that I've seen with some of their other programs. (I'm looking at YOU Sex and the City). More hints and shadows. What makes The Wire so good is the writing. The writing is excellent which happens to be coupled with excellent actors and very competent directing.
The series for its first two seasons does an excellent job of basically showing the realistic obstacles, life styles and challenges of a police department in the city of Baltimore Maryland in dealing with criminals who are far more strategic in their thinking and in their level of sophistication. It is particularly adept at showing how society is harmed by the petty bureaucracies that often exist in our society and within the law enforcement community itself. Anyone who despises or wants to reform government would be well off studying The Wire to learn that the government can do a lot of good but that it is all about how the system itself is designed. People are human and are going to behave like human beings, which is to say good, wonderful, flawed, horrible and greedy.
Even the most heroic characters have their flaws, and even the most vile villains have their good side. This is largely the truth and the screen rarely wastes our time on cartoon characters or two dimensional characters. This is the way Law and Order was meant to be done and perhaps would have been done if it didn't have to be made for the lowest common denominator on Network Television. This is particularly ironic really since the very people the networks hope to capture the attention of are portrayed far more realistically in the Wire. People say "The suits" mess things up, but the truth is, that they really do.
And when you compare "The Wire" to "Law and Order" you really begin to see why.