ROBERT SIEGEL, HOST:
We've been reporting on President Obama's travels in Europe this week. Tomorrow, he meets Pope Francis at the Vatican. The visit comes on the 30th anniversary of formal relations between Washington and the Holy See.
NPR's Sylvia Poggioli reports on the sometimes turbulent history of U.S.-Vatican ties and expectations for the high-profile encounter.
SYLVIA POGGIOLI BYLINE: Marking the anniversary of diplomatic ties in January, the Vatican foreign minister recalled the first high-level bilateral contact in 1788. Speaking in a large Renaissance hall, Archbishop Dominique Mamberti said President George Washington, through his envoy, Benjamin Franklin, informed the Vatican that it did not have to seek authorization from the state for the appointment of bishops.
ARCHBISHOP DOMINIQUE MAMBERTI: In that the revolution that brought freedom to the colonies, first and foremost brought that of religious freedom.
BYLINE: Relations remained friendly until the 1870s. Massimo Franco, author of a book on the history of U.S.-Vatican relations, says that's when the United States was swept up in an anti-Catholic wave.
MASSIMO FRANCO: There were many, many people fearing the Vatican to be a foreign agent trying to re-introduce religion wars in the United States. So, papacy has always been seen as an enemy or anyway as a potential enemy.
BYLINE: What ultimately restored the formal partnership in 1984 was the realization that the U.S. and the Vatican had a common enemy: Communism.
FRANCO: With John Paul II, the Polish pope, we had a turn. Ronald Reagan and the Republican administration felt that the Polish pope might help to give the final push to the Soviet Empire.
BYLINE: There've been some rough spots in the relationship. The Clinton administration clashed openly with the Vatican over population control and abortion. And Pope John Paul II vehemently opposed the two wars against Iraq. More recently, Franco says, the Vatican was dismayed by Washington's backing of the so-called Arab Spring.
FRANCO: In Maghreb and in Egypt and in Syria and Iraq, the Vatican was an objective ally to lay dictatorships. Because they protected Christian minorities because they were lay, they were not fundamentalists, they were not Islamic elites.
BYLINE: There's been much speculation whether Pope Francis will forcefully echo the U.S. bishops' opposition to the administration on a range of issues, and admonish the president on the contraceptive mandate in the Affordable Care Act.
Father John Wauk is a professor at the Opus Dei Pontifical University of the Holy Cross in Rome.
FATHER JOHN WAUK: It could be very friendly. It could be more challenging. And so, reasonable to expect though not necessarily the case, right, that the pope will not gloss over differences between the Catholic Church in the United States and the Obama administration.
BYLINE: President Obama and Pope Francis are likely to discuss a range of international issues: Ukraine, Syria, the Cuba embargo, the plight of minority Christians and perhaps immigration.
In the history of U.S.-Vatican relations, perhaps the biggest novelty is the first non-European pope in centuries. The man analyst Franco calls a post-ideological, global pope.
FRANCO: He is not a son of the Cold War. So all over the world he's not perceived as some of his predecessors, maybe mistakenly as a sort of religious corollary of the NATO alliance.
BYLINE: While the president and Francis share a commitment to social justice and fighting growing inequality, standing next to the pope who denounces laissez-faire capitalism and the ills of globalization, President Obama may appear to be the more moderate of the two.
But Franco rejects the charge made by some American conservatives that Francis is an anti-capitalist.
FRANCO: This pope is a Latin American who saw, in his country and in his continent, all the great injustices created by a wild capitalism. So he wants just capitalism to be more equal, more helpful to the poor.
BYLINE: Francis may be surprised to learn how much the president knows about Catholicism. Not only was he an organizer in a Catholic-run community association in Chicago, when he lived in Indonesia, the young Barack Obama studied at a school in Jakarta named St. Francis of Assisi.
Sylvia Poggioli, NPR News, Rome.