It doesn't matter if the king was mad or causing wars, he was supposed to guard the king with his life. His father infiltrated the city after deceiving the said king and he in the end slayed him, that too from the back. What a coward, and also a cnut. Coward cnut. I really think we need to lynch him tonight if we want to have any chance of winning.
As I said we don't know the full story behind Jaime killing the mad king. Until then, I am not going to judge him.
Coward?! He is one of the least coward persons in Westeros. I'll bet that even without his hand he would accept a duel by any Westerosi challenger.