[halostatue]

Canadian experience suggests you are incorrect about the energies that people will spend against injustice. Canada has had 3-4 relatively high-profile cases in the last decade where long-term prisoners have been exonerated due to the efforts of people who don't want to see injustice.

There are too many instances of prosecutorial malfeasance or justice denied to continue with the death penalty, even in cases where the guilty parties certainly deserve to die (Bernardo and probably Homolka, in Canada).