Terrence Rynne, a U.S. theologian who will be attending the event, said he considers it “phenomenally important.”

“Coming out of it, Pope Francis might see his way clear to articulate a fresh vision of peacemaking to the church,” said Rynne, who helped found Marquette University’s Center for Peacemaking. “That would be wonderful.“

Just war theory is a tradition that uses a series of criteria to evaluate whether use of violence can be considered morally justifiable. First referred to by fourth century bishop St. Augustine of Hippo, it was later articulated in depth by 13th century theologian St. Thomas Aquinas and is today outlined by four conditions in the formal Catechism of the Catholic Church.

A number of theologians have criticized continued use of the theory in modern times, due to the powerful capabilities of modern weapons and evidence of the effectiveness of nonviolent campaigns in response to unjust aggression.

The Catechism currently outlines as one criteria for moral justification of war that “the use of arms must not produce evils and disorders graver than the evil to be eliminated” and notes that “the power of modern means of destruction weighs very heavily in evaluating this condition.”

Conference organizers say in a note to participants about the April event that just war teaching “can no longer claim center stage as the Christian approach to war and peace.”

“After more than 1,500 years and repeated use of the just war criteria to sanction war rather than to prevent war, the Catholic Church, like many other Christian communities, is rereading the text of Jesus’ life and re-appropriating the Christian vocation of pro-active peacemaking,” they state.

“Emphasizing the need to work for a just peace, the Church is moving away from the acceptability of calling war ‘just,'” they continue. “While clear ethical criteria are necessary for addressing egregious attacks or threats in a violent world, moral theologians and ethicists should no longer refer to such criteria as the ‘just war theory,’ because that language undermines the moral imperative to develop tools and capacity for nonviolent conflict.”

As part of their goals for the conference, organizers state they seek a “new articulation of Catholic teaching on war and peace, including explicit rejection of ‘just war’ language.”

They state that they want “an alternative ethical framework for engaging acute conflict and atrocities by developing the themes and practices of nonviolent conflict transformation and just peace.”

April’s conference will be the first to be cohosted by the Vatican’s pontifical council and Pax Christi, an international Catholic coalition akin to Amnesty International that maintains separate national groups in many countries.

Started in 1945 by a French laywoman and a French bishop in the aftermath of the Second World War, Pax Christi has long sought to address the root causes of conflict and advocate for nonviolent solutions.

The conference is being organized around four sessions allowing participants to dialogue and share experiences with one another. The only scheduled talk at the event is to be given by Cardinal Peter Turkson, the head of the pontifical council.

The four sessions are given the themes: Experiences of Nonviolence, Jesus’ Way of Nonviolence, Nonviolence and Just Peace, and Moving Beyond Unending War.

Each of the sessions is being led by experts in the separate topic areas, including: Rose Marie Berger, an editor at Sojourners magazine and social justice activist; Fr. John Dear, a former Jesuit known internationally for his writings and civil disobedience actions; Maria Stephan, a senior policy fellow at the U.S. Institute of Peace; and Lisa Sowle Cahill, a theologian at Boston College.

Rynne said that the participants are hoping their discussions will allow them to draft some sort of document summarizing their sessions. The organizers’ note to participants says they hope to create an “action plan for promotion of Catholic teaching on war and peace, violence and nonviolence.”

Rynne said that participants are coming from many places, including: Chile, Sri Lanka, South Sudan, Tanzania, Kenya, Palestine and Burundi.

“It’s a dream that I’ve had for a long time that the church would embrace peacemaking as its central manta, and not have the just war theory be settled teaching the way it has been for so many centuries,” said the theologian.

“If people understood they had this powerful method of non-violent action that has been demonstrably proven again and again, we would begin to move away” from just war theory, he said.

[Joshua J. McElwee is NCR Vatican correspondent. His email address is jmcelwee@ncronline.org. Follow him on Twitter: @joshjmac.]