Clyde spent 10 years planning every detail of his rampage, taking into account everything from obscure legal precedents to the probable funeral arrangements of Nick's understudy. The only thing he missed? Mere days before the plot, after he stopped researching and plotting, the understudy ditches her old man and gets a new one, Who has the ability to blow the cover provided by his Panama corporation.
More Fridge Brilliance: Clyde said that he was going to "bring down the temple" and that it will be "biblical". He hinted of his own death, just like Samson, which was part of his plan.
Nick insists that the system works, even though he literally let a violent criminal go, just so he could keep a track record going. Did he buy his way through law school or something? Compounding this is that letting a child murderer plea out would destroy any career he might have had as a DA.