John Carr, left, chats with friends and colleagues at his retirement party at the headquarters of the U.S. Conference of Catholic Bishops. (Jahi Chikwendiu/WASHINGTON POST)

For the typical American Catholic, seeing Cardinal Tim Dolan, the country’s top bishop, give the closing prayer at the GOP convention was the big political event of the summer. But for Catholics who know how the church really operates in Washington, something far more significant went down last week: John Carr retired.

For the past quarter-century, Carr has been the most important policy adviser to the country’s Catholic bishops, their Karl Rove on everything from health care to clergy sex abuse. He describes himself as “a 62-year-old, white, round, church bureaucrat,” but Carr’s career is a road map for how Catholicism and politics have mixed in Washington for a generation.

The former seminarian has been lauded by U2 singer Bono for successfully pressing Third World debt relief on Capitol Hill and has challenged Rep. Paul Ryan (R-Wis.), a Catholic, for not demanding more financial sacrifice from middle-class Americans in order to help the poor. When the head of the church’s key mental-health facility for clergy was dying of AIDS in the late 1980s, Carr negotiated how to make the news public. When the Hill’s top poverty advocates were desperate during last year’s budget talks to save assistance programs for the poor, Carr led the effort.

“I’m just so used to John being our leader,” Rabbi David Saperstein, the Reform Jewish movement’s longtime D.C. representative, said last week after describing what he called Carr’s role in convincing a major senator of the impact of climate change on the world’s poor. Carr, it turned out, wasn’t actually at that meeting. But that’s the way it is with Carr — he’s been so influential for so long that sometimes Hill faith lobbyists just assume his involvement in key events.

When a small group of prominent faith advocates organized a good-bye dinner last week for Carr, they intentionally picked “the Captain’s Room” at Ruth’s Chris Steak House.

The mixing of religion and politics engenders powerful passions, but insiders know that faith advocates typically aren’t players in Washington. Carr is one of the few exceptions. But his influence is only part of the reason Carr’s exit Friday is being mourned. Some are also concerned about who will come after him.

At a time when Catholics are watching their community become increasingly polarized along political lines, Carr is considered a dying breed: a Catholic moderate with a foot firmly in both camps. He worked for the White House Conference on Families under President Jimmy Carter and was a Democratic candidate. He has also zealously slammed the Obama White House for its mandate that employers provide contraception coverage to employees. At a good-bye event this week at the U.S. Conference of Catholic Bishops headquarters, Carr’s voice sounded angriest when he bemoaned the Bush-led Iraq War.

Catholics are becoming more divided over whether they focus on church teachings against war and poverty or the ones against abortion and gay marriage. Catholic progressives are particularly worried about Carr leaving as Church officialdom in recent years has put greater and greater emphasis on defending the unborn.

“If John Carr hadn’t been there for the past 20 years, who knows what would have happened?” said John Gehring, who focuses on Catholic issues for the left-leaning advocacy group Faith in Public Life and often clashes with the bishops.

“Whomever they choose is really important,” said Jim Wallis, founder of the progressive evangelical group Sojourners, “. . . whether that person will prioritize Catholic social teaching in a prophetic way and not a political way on the right or the left. Or if the new direction will be more politicized. John is so trustworthy, we’re all praying for who will replace him.”

In fact, it is this feeling of being “politically homeless” that is driving Carr to shake up his entire life. After a semester as a fellow at Harvard University’s school of government, he will return with his wife, Linda, to their home in Cheverly in Prince George’s County and launch a program at Catholic University. He hopes the Center on Catholic Social Teaching and Public Engagement will bring together Catholics from both sides: Democrats and Republicans, those who focus on church teachings against war and poverty and those who focus on church teachings on abortion and marriage.

“Because of circumstances, we can come across as the religion of ‘no,’ and we need to get out of that,” Carr said last week in an office surrounded by boxes, photos of popes and bishops, and posters about campaigns against land mines and poverty.

These are difficult times to be a Catholic moderate. Bishops asked every parish to preach this year against the Obama administration’s contraception mandate that they see as part of a societal war on religious conservatives. Traditionalists feel isolated as polls show most Catholics approve of contraception and same-sex marriage.

But Carr has a disposition to deal with conflict, says his brother, New York Times media columnist David Carr.

“In our family, we call him the velvet hammer. His tone is soothing, but he always gets what he wants. He’s very stubborn,” said Carr, one of John’s six younger siblings.

John Carr was a seminarian — preparing to be a priest — in high school and college, but ultimately decided his calling to spread Catholicism was through politics and policy. Photos from his mid-20s show him as a pro-life Democratic candidate for the Minnesota House, in plaid pants and with long hair. He lost and came to Washington, had four children, became a fanatic Orioles fan and worked through various jobs at the intersection of domestic policy and the church.

For almost 25 years he’s been at the bishops conference, where his title is director of justice, peace and human development — the department that includes a range of domestic and foreign policy issues. The bishops have separate, smaller offices that focus on education, “pro-life” matters and marriage and family life.

The concept of a bishops office sounds like the ultimate in formality, and many Americans already think of Washington as the land of the cold-blooded. But faith advocacy groups — like many advocacy groups — are largely filled with dreamy do-gooders. The conference, for much of Carr’s tenure, was mostly staffed with religious moderates who leaned more Democrat. These days, the focus on religious liberty, marriage and traditional sexuality has sometimes given the impression that the conference leans toward the GOP.

Carr says he feels both parties have abandoned the poor. “Where are the next generation of Sargent Shrivers? Where’s Jack Kemp?”

But some on the left note the bishops’ increased focus on abortion-related issues — their biggest campaign of a generation has been the one against the contraception mandate — and wonder if Carr could have done more to help elevate church teachings about the poor. Some suspect him of being a good soldier, even when he disagreed with the bishops’ priorities.

“John has been responsible for some of the most prophetic writings that came out of the bishops conference” years ago, said James Salt, executive director of Catholics United. “But at a time when millions of people are unemployed [or struggling with faulty mortgages] the bishops’ voice on those issues is near silence. They’re more focused on issues of sexuality. That’s a huge betrayal from my point of view. And some of that blame lies at John Carr’s feet.”

Carr is well aware that both sides feel the other is missing the core issue. Which is what leads him to his next project.

“We can divide up the work,” he said at his farewell party at the conference, “but we cannot divide the church. We are better together.”