When a pope and a president meet, just what are they supposed to talk about?
Judging by the number of statements from different groups looking ahead to Thursday's meeting at the Vatican between Pope Francis and U.S. President Barack Obama, there's a multitude of options.
Among the range of possible topics: the role of the U.S. military in violent conflicts around the world, the likely devastating impact of global climate change in years to come, and continuing disputes between the U.S. bishops and the federal government.
That last one, of course, is sure to be most watched by analysts in Rome and Washington.
Disputes between the administration and the U.S. bishops' conference -- particularly over the implementation of the health care reform law -- are at such a point that Vatican Radio on Wednesday described the upcoming meeting as taking place "in the context of a complex phase of the administration's relations with the Church of the United States."
That phase, the Vatican Radio report said, is "marked, in particular, by controversy on the implementation of health care reform ... and on other issues at the center of public debate in the United States, such as the legalization of homosexual marriages."
Yet many groups are expressing hope that Francis and Obama can find common ground on other issues -- particularly climate change and immigration reform.
Trying to put the spotlight on the latter, 17 people from Los Angeles flew to Rome this week to ask Francis to urge Obama to again push for comprehensive immigration reform.
Members of the group, which included children of Mexican immigrants to the U.S. and left with the blessing of Los Angeles Archbishop Jose Gomez, were pictured in St. Peter's Square on Wednesday holding a sign that read: "Dear Pope Francis: Please help us legalize our parents."
While Obama has backed efforts for immigration reform, he has not been able to persuade Congress to approve a bill on the matter. Although the U.S. Senate passed a measure last June, the Republicans in control of the House of Representatives have still not signaled whether there will even be a vote on the matter there.
A U.S. group that has the backing of more than 50 provinces of men and women religious in Franciscan orders and of universities across the country has asked the pope to push Obama on climate change.
"While many pundits assume that the Pope took the name 'Francis' due to his love of the poor, it's also important to remember that Pope John Paul II named St. Francis the patron saint of ecology," said the head of the Franciscan Action Network, Patrick Carolan, in a statement.
"With that in mind, steps must be taken by both Pope Francis and the President to stop climate change and preserve the earth for future generations."
Likewise, other groups are pushing Francis to speak frankly to Obama about the U.S. military intervention abroad, particularly in the Middle East, where Christian minority populations in some places are close to extinction.
Francis himself signaled his dislike for U.S. military strikes in September, when he hosted a four-hour vigil in St. Peter's Square attended by a crowd of some 100,000 pilgrims to push for peace without military intervention in Syria. During that event, the pope declared: "Violence and war are never the way to peace!"
Another possible issue for discussion Thursday: U.S. policy toward Cuba, which has liberalized its economic policies in recent years following the 2011 resignation of Fidel Castro as its leader.
Both the U.S. and Cuban conferences of Catholic bishops have called on the U.S. to drop its trade embargo against the country, as did Popes John Paul II and Benedict XVI.
"Pope Francis will have the opportunity to express the shared views of the Cuban and U.S. Catholic Bishops, urging President Obama to dialogue with Cuba over the issues that divide the two countries, rather than continuing the U.S. embargo," the Washington Office on Latin America's program director, Geoff Thale, said in a statement.
No matter what the topics of discussion, many statements leading up to Thursday's meeting seem to agree that the encounter is one worth praying about.
Francis and Obama, said the Catholic Democrats in their statement, "face the burdens of addressing the daunting challenges of poverty and inequality, world peace, and making the preservation of God's creation a priority for all nations."
"This week in particular, they deserve to have us pray for them," said that group, pointing supporters to popeandpresident.net, where people can sign a statement saying they intend to pray for the encounter.