Is death penalty moral or immoral?

It is moral because it is peaceful

The fact is that the death penalty, like limb-chopping or stoning, is a morally outrageous practice whatever its deterrent effect: it reduces society to the ethical level of the murderer. In a society that aspires to be moral and just, there is no room for such a state-sanctioned uncivilized practice.

Explanation:

Capital Punishment in the United States

In 1972, the United States Supreme Court suspended the imposition of the death penalty, finding it unconstitutional because it was imposed disproportionately on minorities and the poor ... Many proponents of the death penalty argue that it deters criminals from killing.