I've written about Marshal Law before. The violent, satrical, take-no-prisoners character is a favorite of mine. He wears a bondage mask, has barbed wire wrapped around his arm and kills people for a living. What's not to love? The various series he's been a part of have all been over-the-top when it comes to violence (see the panel here for an example). It's not meant to be real or even realistic. It's a satire. Nothing more. Nothing less.
When the series came out in the late '80s a friend of mine thought it was pretty ghastly and had called it the "downfall of comics." (I am reminded of this by him in a recent e-mail where he had read my original post online.) This observation comes from a person who had recently got into the art form and had no real knowledge of comic books' history with violence (something well-documented by writers better than I), nor the shifting tastes of what a public wants in entertainment. He made a casual observation based on his thoughts and feelings, and, as he is quick to admit, he made it without doing more than glancing at the first issue.
The world of Marshal Law is full of steroid-abusing men in tights who pummel each other until bones break from skin. People are set on fire at random, and gun violence is as common as candy in the schoolyard. Marshal Law is employed to take down wayward heroes, and he does it with all the violence one would expect. The entire concept is taking the idea of superheroes to what is really the next level, as seen in books like The Authority, which came well after Law and company. The only thing that makes Superman any different is the level of violence. The Man of Steel punches a guy and he goes down. His head doesn't go flying off into space. Why wouldn't it, though? Why wouldn't pumping an unstoppable behemoth full of bullets result in a wet mess of flesh still coming at you with a look of rage? The creators of the Marshal Law character, Pat Mills and Kevin O'Neill, asked those questions and showed the results of their findings. They did so in a way that was so outrageous, however, that you couldn't help but notice what they were trying to accomplish. Heavy-handed? Perhaps, but that was really a great way to tell the story.
The various titles starring Marshal Law didn't destroy comics, and nor did it have any real noticeable impact. It may have inspired a few creators (I hope it has), but it didn't change the art form in any way that is lasting. It didn't need to, however. It came onto the scene and made its point. That is far more than many comics do these days.