We can learn a lot from people who left the church, whether we can win them back or not.

For generations, the Baltimore Catechism taught that Catholics who miss Sunday Mass through their own fault commit a mortal sin, making the soul an enemy of God, depriving it of the right to everlasting happiness in heaven, and making it fit for everlasting punishment in hell.

These teachings helped fill the pews of Catholic churches for decades, but today nearly two thirds of U.S. Catholics do not attend Mass weekly. For many, the church is not a relevant force in their lives. Others, however, love the church in which they grew up but are at the same time angry with it. They may disagree with the church’s teachings on divorce, remarriage, homosexuality, or birth control. They may have become fed up with a certain priest. They may be angry with changes that have or have not occurred since the Second Vatican Council.

“Alienated Catholics are Catholics for whom their Catholic faith is very important but who feel that they have been excluded or driven away by the church,” says Jesuit Father Mark Horak, contrasting alienated Catholics with those who feel the church offers them nothing of value. “This feeling of having been excluded may or may not be well-founded, but it is real. The good news is that alienated Catholics are likely to return to the church if they can somehow be reconciled.”

As millions of Catholics have drifted from the church and then back to it, many have stepped forward to welcome them. A ministry of welcoming alienated Catholics has sprung up in the last few decades, and in many cases, these ministries can teach some lessons to the greater church.

1. Time away from the church can be spiritually productive.

“Righteous, respectful anger has a place in the church,” says Mary Christine O’Connor, adjunct professor of theology at St. John’s University in New York. “Anger and love are just a hair away from being the same thing. If people didn’t care, they wouldn’t be angry.”

Even when that anger leads people out of the church, it may still contribute to the overall spiritual growth of the person, says Paulist priest Jim Moran, director of Landings International, a 10-week, parish-based program that helps alienated Catholics return to the worshiping community. Moran has directed the program for four years and says one of the quotes that inspires him most comes from the book of Proverbs: “I, wisdom, dwell in experience.” He raises eyebrows when he asks returning Catholics, “What wisdom has God brought to you in this experience of being apart from the faith? Why did the Spirit lead you out of the church?”

Father Peter Cullen, rector of St. Paul’s Episcopal Church in Brooklyn, sees firsthand the wisdom that people gain while outside the Roman Catholic Church. Many Roman Catholics come to St. Paul’s seeking a smaller worshiping community, a more inclusive environment, or the sacrament of Matrimony for a couple unable to marry in the Roman Catholic Church because of its rules on divorce.

St. Paul’s is considered an Anglo-Catholic parish, and as such Masses include all of the accoutrements Roman Catholics grew up with: stained glass windows, statues, candles, incense, and a communion rail that still serves its original purpose. What it lacks is the teaching and preaching on sexuality that turn many Roman Catholics away from their own church.

Cullen finds that while alienated Catholics may find a home in his parish, it is often temporary.

“Ninety percent of disaffected Romans who come to St. Paul’s do not want to be Anglican, they want to be Roman,” says Cullen, adding that he, too, wants them to be Roman. “I think the gravity of Rome is very, very strong and is always a presence in their lives.

“These Catholics need to get away to get a sense of perspective,” he adds. “From a distance, they realize a lot of times that they are not leaving the Catholic faith, but they’re leaving a particular priest or a localized Catholic expression of the Catholic faith.”

In Cullen’s parish they find a space to work out problems they have with their own church—and prepare them for an eventual return home.

2. We just want a clear explanation of church teaching.

When alienated Catholics engage Cullen in discussion, the Anglican priest finds himself doing apologetics for the Catholic Church, often explaining its teachings and the many demands placed on its priests.

“One of first things I always have to do is listen to stories of priests who have yelled at them,” Cullen says, “and I have to know more about Roman Catholic marriage law than my own.”

Joan Horn, a coordinator for Landings International, says many of the alienated Catholics she encounters are misinformed about church teaching.

“Many years ago, maybe someone’s aunt told them they were excommunicated because they were divorced,” she says. “And when you’re away from the church, you’re often not in touch with Catholics. Landings puts people who have been away in touch with people who can answer their questions.”

Although not always available, discussions of church teaching can have an impact on Catholics struggling with the church.