Rev. Msgr. Lorenzo M. Albacete

Msgr. Lorenzo Albacete, a former aerospace researcher turned Roman Catholic priest who became one of the Vatican’s most articulate, unofficial defenders in the United States, died on Oct. 24 in Dobbs Ferry, N.Y. He was 73.

The cause was complications of Parkinson’s disease, said Louis Giovino, a spokesman for Communion and Liberation, a lay movement for which Monsignor Albacete worked.

Monsignor Albacete (pronounced ahl-bah-SET-ay) occupied many positions in the church, both official and unofficial. He was a theology professor, a college president and an adviser to bishops and cardinals. He was a confidant of two popes, an emissary to American literary circles and a frequent guest on the Bill Moyers and Charlie Rose public television programs, where he offered a Catholic insider’s perspective on events like the Sept. 11 terrorist attacks and the church sexual abuse scandals.

He was a consultant to several PBS “Frontline” documentaries on the church; wrote articles about religion, some for The New York Times Magazine and The New Yorker; and, in 2003, published a collection of essays, “God at the Ritz,” which made the case for Christian faith in a science-based culture. (A reviewer for the neoconservative magazine The Weekly Standard, praising the book, said of its author, “Maybe you haven’t heard of him, since he spends most of his considerable talent reaching out to liberals.”)

Lorenzo Albacete was born in San Juan, P.R., on Jan. 7, 1941, one of three sons of Lorenzo Albacete and the former Conchita Cintrón. His mother raised the children. His father, who worked for a shipping company and died when Lorenzo was a teenager, was a man of fierce anticlerical beliefs who opposed young Lorenzo’s wish to become an altar boy.

After graduating from a Catholic high school in Puerto Rico, he attended the Catholic University of America in Washington, where he majored in physics and aerospace science and received a bachelor of science degree. He then worked for seven years at the Naval Ordnance Laboratory in White Oaks, Md., a weapons facility. (It closed in 1991.)

Mr. Albacete was in his late 20s and planning to be married when he broke off the engagement and entered the Theological College at Catholic University to study for the priesthood — a decision he made after years of resisting “every indication of a priestly vocation,” beginning with wanting to be an altar boy, he wrote in a Times Magazine column in 2002.

Ordained at 32 in 1973, he became an assistant to the archbishop of Washington. Three years later he was assigned to be a guide for a visit by Archbishop Karol Wojtyla of Krakow, Poland.

The two developed a friendship through their shared interests in theater, literature and philosophy and remained friends after Archbishop Wojtyla became Pope John Paul II in 1978. Through the pope, he became a friend and confidant of Cardinal Joseph Ratzinger, who became Pope Benedict XVI in 2005.

Monsignor Albacete is survived by a brother, Manuel.

He was appointed theological adviser to the nation’s bishops during a 1980 Synod of Bishops at the Vatican; taught at pontifical institutes in the United States and Rome; and was rector of the Pontifical Catholic University of Puerto Rico from 1996 to 1997. In his article “The Poet and the Revolutionary,” which appeared in The New Yorker in 1998, he recounted Pope John Paul II’s visit to Cuba and the pope’s meeting with Fidel Castro.

In his last decade, Monsignor Albacete helped establish a New York-based educational arm of Communion and Liberation, a conservative international movement of lay Catholics founded in Italy.

Returning to Washington in 1979 as pope, Cardinal O’Malley said, John Paul II greeted Father Albacete in a receiving line, fixing him with a look roughly equivalent to a grab of the lapels and saying, “Lorenzo, maybe now you will answer my letters?”