Originally Posted by
Somecrazyaussie
It is. A good defense attorney could easily spin the Joker's actions as being born from a deranged mind. For starters, he took a dip in a chemical bath. An experience that is highly traumatic. They could also argue that the chemicals screwed with him on a biological level. Fundamentally altering his brain chemistry.
If the Joker just straight up killed (shooting them etc) people, he could be in trouble. But the way in which he goes about killing them often involves methods that are so bat-shit crazy that there is no doubt he isn't right in the top block.