VATICAN CITY — Two weeks after ascending the throne of Saint Peter, the first pope from the United States is being floated by world leaders for another pivotal role: peacemaker between Ukraine and Russia.

The initiative to have the Vatican mediate talks between Moscow and Kyiv could be an early test for Pope Leo XIV, who, in the past, has taken a more overtly pro-Ukrainian stance than his predecessor. But Leo has also seized on conflict resolution as an early driving theme. Playing a role in ending Europe’s worst conflict since World War II could help define his early papacy.