VATICAN CITY — When Pope Francis visited the United States two years ago, he spoke out against the death penalty in speeches to Congress and the United Nations. This week he went a step further, calling for a revision of official church teaching that would make capital punishment “inadmissible.” It was a historic shift given that the death penalty has, until now, been allowed by the church in certain circumstances. The death penalty, Francis explained during an important speech in the Vatican on Wednesday, is “contrary to the Gospel, because it entails the willful suppression of a human life that never ceases to be sacred in the eyes of its Creator.” With these words the pope is also reshaping what it means to be “pro-life.” He is moving it away from primarily opposing abortion and stressing that it means protecting life at every stage, from womb to natural death. It is in the U.S. where the pope’s words may have the most impact, given punishment by death is still legal in more than 30 states and is supported by close to half of all Catholics. According to a 2016 Pew Research poll, 43% of American Catholics support the death penalty, while 46% are opposed. And abortion remains a highly polarizing issue. Among those welcoming the pope’s words was Sister Helen Prejean, whose work on death row was dramatized in the Oscar-nominated film “Dead Man Walking,” with her role played by Susan Sarandon. “At last, a clear, uncompromising stance of moral opposition to the death penalty by the highest authority of the church,” she told America magazine. There are many more-traditional Catholics who argue forcefully in favor of the death penalty. Joseph M. Bessette and Edward Feser argue that “for extremely heinous crimes, no lesser punishment could possibly respect this Catholic principle that a punishment ought to be proportional to the offense.” Defenders of the death penalty on religious grounds also point to the argument from St. Thomas Aquinas, the renowned church teacher, that sometimes it is permissible in order to promote the common good and keep people safe.