Peter Berger reports that more religious citizens are—-counter t0 many assumptions—- actually less likely to support the death penalty:
Support for the death penalty correlates negatively with degree of religious involvement 65% in favor among those who attend services weekly or more, 69% among those who attend monthly, 71% of those who attend rarely or never. There are interesting differences as between religious groups 71% of Protestants are in favor of the death penalty, 65% of Catholics, 57% of those with no religious preference. There has been a notable decline in support among Catholics (possibly due to recent teachings about a culture of life by the Catholic Church). Across all denominations, Christian as well as Jewish, religious conservatives are more in favor of the death penalty than religious liberals. Not surprisingly, this difference is very visible within Protestantismamong clergy and lay people, and in official positions of church bodies. All mainline Protestant churches have made abolitionist statements, while Evangelical churches (notably the Southern Baptist Convention) have supported retention.
Note that Catholics have become more opposed to death penalty even as the Church has taken what many call, wrongly, a “conservative” turn. Keep this in mind when you hear shrill accusations of the Church becoming nothing more than another Republican Party lobby.