@redwingx: The rest of the DCU can hardly clean up their own problems, they don't have time for Gotham's criminals. And people like Spectre can kill Luthor too but I don't see you making a thread about that.
It is said that Gotham is the worst city. You would think that the rest of the world would do something. The Justice League is formed to fix problems that the hero can't do alone and a corrupted city is a big deal.
Also are you really comparing Luther to Joker? Joker is downright evil and Luthor is currently a member of the JLA.
You can easily make Joker a member of JLA too,it's up to the writer.