WASHINGTON — When it comes to religious affiliation, a distinctive pattern has emerged in President Donald Trump’s new administration: Most of the high-ranking appointees to military-related positions hail from a Catholic background.

That includes not only Gen. James Mattis, who was sworn in as secretary of defense in late January, but also the new secretary of the Department of Homeland Security, Gen. John Kelly. The pattern holds with the national security adviser, Michael Flynn, who is also a general and grew up in an Irish-Catholic family in Rhode Island.

Other high-ranking Catholics include the Army secretary appointee, Vincent Viola, an Army veteran and major donor to Fordham University; and Gen. Joseph Dunford, who was tapped to serve as chairman of the joint chiefs of staff under President Barack Obama and is viewed as likely to continue in that role.

That so many Catholics ended up in top military positions is not necessarily by design, but it is nonetheless significant, according to several military historians.

Lisa Mundey, a military historian at the University of St. Thomas in Houston, said the appointments reflect broader social trends. “I think what is interesting is how well Catholics are integrated into society [now] than they were historically,” Mundey said. A key turning point was the election of John F. Kennedy as president in 1960, which especially paved the way for other Catholics to serve in key government posts, according to Mundey.

Another watershed moment was the end of the draft and the birth of the all-volunteer army, in 1973. Since then, more of those who serve in the military have been making their careers there, according to Mundey.

The armed forces provide an environment that is friendly to the expression of faith, according to William Leeman, a military historian at Salve Regina University in Newport, Rhode Island, who formerly taught at West Point. “They seem very comfortable with their religion, in the sense that it seems to be a more conservative environment,” Leeman said.

For those in the military, their faith can help them get through the hardships they face, becoming an important part of their service, Leeman said.

The military also places a high value on ethics and character education, Leeman noted. “And certainly an individual’s faith is going to be informing that,” he said.

James Mattis

The role of faith and character in shaping military leaders is well-reflected in Mattis.

A former Marine who served under him recalled his dedication. “I think what really stood out to me, though, was his fatherly approach to his troops,” said Pat Lynch, who served two tours in Iraq and rose to the rank of captain before leaving in 2010. Mattis was the commanding officer of the I Marine Expeditionary Force while Lynch was in the unit.

“Between my two Iraq deployments, I got stuck with duty on Thanksgiving Day. I was sitting in the regimental headquarters building, expecting it to be a really slow day, when I looked out the window and saw an old man with three stars on his collar walking up. Gen. Mattis had decided to come on to base and thank all of the Marines serving duty on the holiday. He gave us some cookies and spent about 15 minutes chatting with us before moving on,” Lynch recalled.

A formal biography of Mattis provided by the Trump transition team described him as “the living embodiment of the Marine Corps motto, Semper Fidelis,” Latin for “always faithful.”

Mattis also epitomizes the soldier-scholar ideal that the military has cultivated among its career officers since it went all volunteer in 1973, according to Mundey. Mattis has a reputation as a voracious reader who sports a library of 6,000 books, ranging from T.E. Lawrence’s Seven Pillars of Wisdom to a history of Alexander the Great. His passion for reading became widely known after military historian Jill Russell publicized an exchange of emails with the general, in which he stressed the importance of reading for his officers.

His endless reading, combined with his bachelorhood, has earned him the nickname of the “warrior monk.”

“These people appear to be the best in what they do,” said Jim Formato, a Vietnam veteran and a spokesman for the National Catholic War Veterans. He described the appointments of distinguished Catholic generals like Mattis as a feather in the cap of the Catholic Church.

John Kelly

Gen. John Kelly, the new head of the Department of Homeland Security, like Mattis, is known as a committed Catholic. A Boston native raised in an Irish-Catholic family, Kelly served in the Marines and commanded troops in Iraq before heading up the U.S. Southern Command, from which he retired early last year. Kelly’s son, 1st Lt. Michael Kelly, served in the Marines in Afghanistan and was killed by a land mine.

According to emails published in The Washington Post, Kelly said he had turned to his faith for support as a worried father. “We are doing a novena a minute down here, and there is no end in sight,” Kelly said in one message to family members. “Pray. Pray. Pray. He’s such a good boy ... and Marine,” he told his older sister in another email.

Kelly’s character — especially his quiet resolve in the face of personal loss — has earned him respect and plaudits inside and outside the military.

“John Kelly is among the finest generals of his generation, dedicating his life to our country. His character, service and sacrifice set an example for his Marines and for all Americans. We’re all blessed that he’s once again answered the call to duty,” said Arkansas Republican Sen. Tom Cotton in a statement provided to the Register.

The Register requested an interview with Kelly while his nomination was pending and was told by the Trump transition team that the general was declining interviews during the confirmation process.

Vincent Viola

Unlike Kelly and Mattis, Viola did not make his career in the military. Instead, he is a businessman who founded a high-frequency trading firm, Virtu Financial, and is also owner of the Florida Panthers. He has deep ties to Fordham University, where, in 2009, he donated $2 million to endow a chair named after Jesuit Cardinal Avery Dulles.

In a news release announcing the endowment, Viola praised Fordham for teaching “the bedrock principles of service.” In addition to being a donor, Viola is also a former trustee and parent.

“In all of those roles, he has done much to advance Fordham’s Jesuit, Catholic mission and strategic priorities, and we are deeply in his debt,” said Jesuit Father Joseph McShane, the president of Fordham.

The Influence of Faith

The preponderance of high-level Catholics in military or related positions in the administration raises the question: To what extent might their faith influence their policy decisions and the advice they give President Trump? Some have broken with Trump in areas where he is in conflict with Church teaching. Perhaps most notably, Mattis has expressed his belief that torture does not work. Kelly also has said laws forbidding waterboarding should be followed.

Mattis is on record as valuing the counsel of the Church — albeit in this instance in a battlefield context. In a 2003 interview with PBS, he explained how he leaned on advice from a chaplain in deciding how to win over Iraqis. “On the suggestion of my Catholic chaplain, the Marines would take chilled drinking water in bottles and walk out amongst the protesters and hand it out. It is just hard to throw a rock at somebody who has given you a cold drink of water, and it’s 120 degrees outside,” Mattis said.

National Catholic War Veterans’ Formato said he expects a servicemember’s faith to deeply shape how he or she approaches duty: “A military person who is a practicing Catholic is someone who, I think, has guidance.”

Stephen Beale writes from Providence, Rhode Island.

Note: Archbishop Timothy Broglio of the Archdiocese for the Military Services, was unavailable for a comment for this story due to an extended trip, according to a spokesman.