ROME - Two weeks ago, it was Joschka Fischer, the German foreign minister. Last week, it was Tariq Aziz, the deputy prime minister of Iraq. And today, if they keep to the schedule, it will be Tony Blair, the British prime minister.
As the prospect of an American-led military strike against Iraq looms ever larger, world leaders are beating an increasingly well-worn path to Pope John Paul II's door to talk about the wisdom of, and rationale for, war.
In the process, they are demonstrating a faith, or at least hope, in the power of the pope to sway international opinion and the power of a visit with him to reflect well on their own positions.
"We are witnessing the latest and greatest global debate in a long time on what would and would not be a just war," said Michael Emerson, a senior research fellow at the Centre for European Policy Studies in Brussels, Belgium. "So the moral authority of the pope is being solicited by both sides."
The pope has repeatedly stated his opposition to a war in Iraq under current circumstances, and his conversations with world leaders, including a meeting here this week with the U.N. Secretary-General, Kofi Annan, allow the pope to press his case.
But while the world leaders themselves usually request these meetings, often when they are here on other business, the Vatican has its own interests. Those include a commitment to peace as well as the protection of Catholic and Christian minorities in predominantly Muslim countries, including Iraq.
The meetings themselves are intensely private: None of the participants ever disclose enough to make clear precisely what, or how much, the pope says.
But Vatican City serves as a dramatic and singular stage for the officials who travel there. Western diplomats assigned to the Vatican say world leaders who meet with the pope are clearly seeking to cast their concerns and deliberations in a high-minded light.
"The pope is such a respected figure, with such great moral authority and prestige, that for anyone to come and visit him gives them a lot of illumination and, in some cases, for those who need it, legitimacy," said R. James Nicholson, the American ambassador to the Holy See.
Aziz held a news conference after he saw the pope, making prominent mention of that meeting.
Fischer, too, spoke to reporters after his visit, saying that he and the pope had had a "very serious and very open talk" about the consequences for civilians of a war in Iraq, which Germany opposes.
"With our deep worries and our deep skepticism, we are very close," Fischer said, referring to German and Vatican officials.
Blair finds himself at odds with the Vatican about the justification for such a military strike against Iraq.
But foreign policy experts and diplomats said that with a visit to the pope, Blair would send a message that he was not dodging moral considerations in coming to a belief about the possible need for military action. Blair, a Christian whose wife is Catholic, has repeatedly talked about the moral case for a war.
While President Bush has not sought an audience with the pope, Nicholson arranged a visit to the Vatican last week and a public speech here by Michael Novak, a conservative American theologian who maintains that a war would be morally defensible.
The meetings with the pope show that he is not just the titular leader of an estimated 1 billion Catholics worldwide. He remains, in Western democracies, a religious leader with unrivaled recognition: a point of reference in debates with clear moral dimensions.
The meetings also show the depths of the Vatican's objections to war, and they are only part of its efforts, which included a trip by a papal envoy to Baghdad.
Vatican officials are worried about the effects of a war in Iraq on relations between Christians and Muslims, a matter that the pope mentioned during brief public remarks on Thursday.
"They really don't want Christian martyrs," said a Western diplomat assigned to the Vatican.