While the diplomatic maneuvering between the Holy See and Muslim leaders has taken several striking turns in recent weeks, the Vatican's strategic purpose in this conversation has been clear since Pope Benedict XVI's 2006 Christmas address to the Roman Curia.

There, while reflecting on his September 2006 Regensburg Lecture and his December 2006 visit to Turkey, the pope suggested that the Church's future dialogue with Islam should focus on the positive achievements of the Enlightenment, especially religious freedom understood as a basic human right and the separation of religious and political authority in a justly governed state. Regensburg and the Curial address set off a kind of inter-religious chain reaction.

In October 2007, 138 Muslim officials from around the world issued "A Common Word Between Us and You." Addressed to the pope and other Christian leaders, the "Letter of 138" proposed a dialogue based on the two great commandments of love of God and love of neighbor.

As I wrote at the time, while the call to a deeper conversation was welcome, the "138" seemed to be trying to change the subject --- for there was no mention in their letter of what the pope had proposed discussing in the December 2006 Curial address.

Last Nov. 11, Cardinal Tarcisio Bertone, the Holy See's Secretary of State, wrote to one of the "138," the Jordanian prince Ghazi bin Muhammad bin Talal, accepting the call to a deepened conversation, suggesting that a representative delegation of the "138" come to Rome to meet with the pope, and proposing three topics for dialogue: "effective respect for the dignity of every human person"; "objective awareness of the other's religion"; and "a common commitment to promoting mutual respect and acceptance among the younger generation."

In an authoritative commentary on Bertone's letter, Father Samir Ghalil Samir, an Egyptian Jesuit and Vatican advisor on Islamic affairs, noted that the cardinal's letter to the prince had tried to get the conversation back on the track proposed by the pope the previous December: religious freedom and the separation of religious and political authority in the state. Father Samir also noted that several signatories among the "138" had indicated that they were not much interested in discussing those topics.

Last Dec. 12, Prince Ghazi wrote to Cardinal Bertone, accepting the invitation to a meeting in Rome (which will likely take place in March). At the same time, the prince once again tried to change the subject, suggesting that the primary focus of dialogue should be the "intrinsic" questions raised by "A Common Word Between Us and You" (i.e., the two great commandments). At some future point, the prince suggested, "extrinsic" questions could be addressed.

A close reading of the prince's letter suggests that his "extrinsic" questions are what the pope has gently but persistently insisted be the primary questions for today's conversation: the natural moral law that can be known by reason; religious freedom, other human rights, and the natural moral law; religious freedom; civil equality between men and women; the separation of religious and political authority in the state.

There is a considerable gap here. The pope has made clear what the objectives of the dialogue should be; Benedict's conviction is based on the Catholic Church's 19th and 20th century experience of wrestling with the question of religious freedom and other challenges posed to religion by the modern state. The "138," as represented by the Jordanian prince, keep trying to change the subject. The exchanges are polite, but the gap is unmistakable. And the gap is not accidental.

For as I discuss in "Faith, Reason, and the War Against Jihadism" (Doubleday), it is precisely the issues the pope identified in his December 2006 Curial address that are at the root of the conflict between jihadist Islam and the rest of the world (including reformist elements within Islam). Can the gap between what the Pope proposes as a dialogue agenda and what the "138" have proposed be bridged at the March meeting in Rome? The answer to that question will be the measure of the meeting's success.