Giuseppe Pelli never completed his dissertation against the death penalty, the first of its kind. He belonged to a small group of Catholics critical of their Church from within, but essentially conservative in their thinking and attitudes. Pelli’s research was heavily weighted toward the natural philosophers from Grotius on, and he exploited their knowledge of the ancient sources. Montesquieu apart, Pelli showed little interest in the Transalpine Enlightenment. He found in Montaigne a kindred spirit, a writer of conspicuous humanity who expressed his views without inhibition. As a loyal Catholic, Pelli’s basic argument against capital punishment was that it is inconsistent with Christianity. God is everywhere in Pelli’s work. Natural law is decisively God’s law, which could never have countenanced capital punishment imposed by human agencies. Pelli held back from direct attack on the powers-that-be, judicial and ecclesiastical. His diagnosis is Augustinian: the root of the problem is sin, to which the whole of humanity is susceptible. Pelli’s work is the best that devout, conservative Christianity could offer at this stage in history.