Although I oppose the death penalty, I think I can say that for the most part the U.S. executes only people who have committed particularly horrendous crimes. And I'll say it again - this is a relatively new development. Prior to about 1850, the majority of executions in "civilized" nations were for political reasons - either to eliminate political opponents, or to exert the authority of the ruling class over the lower class by executing people suspected of committing relatively insignificant crimes. England's Black Act of 1723 instituted the death penalty for over fifty offenses.

-Joe-