There is a blog called Law and the Multiverse, in which two lawyers write entertaining and earnest posts that are occasionally mind-bending in their level of detail about how existing laws would be applied to superheroes. The blog started in November 2010, and they've already been written up by BoingBoing, Volokh Conspiracy, and the New York Times.
It's a fun way to look at the law, I guess, and an interesting (if not completely original) take on superheroes, whose absurdity is often too easy to take for granted. However, there is one major, Mjolnir-sized hole in the logic underlying the blog.
All of the laws that Law and the Multiverse examines would not exist in a world inhabited by superheroes.
Occasionally, comic books attempt to look at what would happen "if superheroes actually existed." Perhaps the most famous and fully-realized of these works is Watchmen (and that book kind of cheats, since there's really only one character with super powers and he works for the government anyway). Back in the 1940s a few superheroes like Captain America and Spy Smasher used the war as starting points for their stories. Mostly, however, you got very half-assed acknowledgements of the real world, like for instance the "World's Finest" -- Batman, Superman, and Robin -- selling war bonds on the cover of one of their comics:
You can read the rest of this piece over at When Falls the Coliseum, if you're so inclined.