Throughout the entire run of the show, it grabbed you by the throat and never let go. Beginning with the greatest shocker ending of any TV pilot (I can't ruin it for anyone who hasn't seen it yet) and introducing in Vic Mackey the most charismatic anti-hero in moden television, the show took standard police drama and made a show that, contrary to 'Law & Order,' is not about the criminals, but the cops themselves.
Watching Mackey and his elite Strike Team - who operate in the rough-and-tumble (and fictional) Farmington district of L.A. - navigate the criminal underworld cutting illegal deals and playing people against one another is like watching lions kill a baby buffalo: you want to be repulsed by their tactics, but you also can't help marveling at their brutal efficiency.
In many ways, Vic Mackey is the embodiment of what is wrong with the war on crime: bosses want stats, and as long as his unit is bringing in arrest numbers and drug seizures, he's got plenty of friends in the department who are more than willing to look past his methods.
But as the show illustrates time and time again, the cops in Mackey's unit are marshals in a lawless town. The gangs in Farmington know only violence, making shortcuts an all-too-easy option. Who's going to believe a drug dealer that says you beat a confession out of him if you also nail him with 10 kilos of cocaine? Will anyone really care that you had to beat a pedophile with a phone book if it got him to tell you where he was hiding a 7-year-old girl?
One of Mackey's co-workers puts it perfectly in the first episode: "Al Capone made money by giving the people what they wanted. These days, people want to come home and see their stereo still there... they want to hear about a murder on the news, and read the next day that the cops got the guy. If that means some n*gger, some sp*c gets roughed up in the barrio, well, as long as they're concerned, it's don't ask, don't tell."
The show was modeled loosely on the real-life Ramparts scandal in the LAPD, which had a unit very similar to Mackey's Strike Team: they targeted gangs and drug traffickers in the worst parts of LA, and were given wide latitude to operate. What happened, essentially, was that they started taking shortcuts, taking kickbacks from drug dealers and busting their competition to create a win-win situation for both the dealers, who get a monopoly on the local drug market, and the cops, who get quiet streets with no murders to deal with... ideally...
What HAPPENS, of course, is that one shortcut leads to another and pretty soon you're in waaaaay too deep. This is where 'The Shield' begins to dovetail from 'The Wire.' Where 'Wire' characters do have flaws, there are very few outwardly corrupt police; just a lot of career men with aspirations of a bigger desk that gum up the works. The 'Shield' presents a set of police who all have their own deep flaws: Det. Claudette Wyms, while she may be the moral compass of show, has also shown flashes of arrogant moral superiority. Mackey's commanding officer for much of the show's run, Capt. David Aceveda, is one of the aforementioned career men, who needs Mackey's stats to help him eventually get elected to city council on a crime platform, but can only turn a blind eye to his methods for so long.
Really, though, I think it's the show's pace that elevates it above most of the other police procedurals/dramas on TV. Every scene is pushing the story forward, and usually, someone is in trouble or danger all the time. The series also has some of the best twists, turns and shockers you'll ever see. Let's not forget, there was a bit of controversy when 'The Shield' first came out over how raw it was for cable TV. People get FUCKED UP on 'The Shield' (especially, it turns out, when you cross the Armenian mob, who like to chop people's feet off), and there aren't a whole lot of happy endings.
But it's not nearly as dark as 'The Wire.' It's a high-pressure look into the lives of corrupt cops who are trying to do right despite their very-serious flaws. I'll tell you what: here's the real reason I love it so much. 'The Shield' was the first show where I found myself, literally, at the end of of every episode, looking over at my girl and being like, "...HOLY SHIT, WHAT THE FUCK IS GONNA HAPPEN NEXT?!?" We blew through the first three seasons in three straight weekends. No joke. So if you haven't already, start with season one, and if you rush, maybe you can make it in time to be up to speed on the final season.
You'll thank me later.