Maximizing human happiness?

@prometheus Some humans would be happier that other humans would be dead. Whose happiness are you maximizing?

Those deserving death or those that bring about human death?

@Word are "those deserving death" deserving of it because they broke a law with a capital punishment?

In general I think laws of the land and their consequences should be followed - but that the laws and consequences should be continually under revision to ensure they are having the desired outcome.
AFAIK execution is the only way to guarantee no recidivism, however in my opinion the risk of wrongful conviction is way too high to allow it (I've seen a figure of 4% for the USA).

The law aside I think in almost all cases where someone wants to see someone else dead they could be almost if not actually as happy if that person was just no longer influencing their life in any way. And to me all the arguments that would allow someone to kill another person ultimately lead to a society that is worse for everyone and that negative for all of society outweighs any individual positive. In much smaller groups the math may be different, but multiplied by 330 million, or 7.6 billion it really only takes a tiny negative for each person to outweigh any individuals net positive happiness.

But I won't pretend this math is easy - definitely much harder than calculating the tip and who owes what at a restaurant.