Resolved: A just society ought not use the death penalty as a form of punishment.Obviously, the overwhelmingly important definition in this (lovely, philosophical, non-policyesque for once) resolution is the meaning of "just."
Get your brain back in gear with a trip to the Stanford Encyclopedia of Philosophy's article on Legal Punishment.
Some terms to consider: retribution, restoration, prevention, deterrence, desert, consequentialism.
More coming soon.
Update 8/17: I ask some mathematical questions about executing innocents.
Update 8/20: I parse the resolution.
Update 8/26: What's the relationship among capital punishment, democracy, and a just society?
Update 8/29: I tentatively delineate the distinction between private morality and public justice.
Update 9/1: How can a satirical newspaper illuminate our understanding of the death penalty?