Before long, the mission broadened to include advocacy. Members would stick fliers on the windshields of cars parked at a church during Mass warning that an abusive priest was inside. Victims stood outside cathedrals and even on St. Peter’s Square at the Vatican holding photographs of themselves as children when they were first molested.

Ms. Blaine told her story to the local news media in Toledo, and her abuser was removed from ministry after more of his victims came forward. She received a settlement from the church.

“She wasn’t trying to change the world; she was trying to heal herself,” said Barbara Dorris, the managing director of the Survivors Network and an early participant in the group. “She was trying to work within the church, but Barbara couldn’t because the systems failed her and her perpetrator was still out there. She felt, like every victim feels, that there’s this responsibility to speak up before what happened to you happens to someone else.”

In 2002, after a vast cover-up of abusive priests in Boston was revealed by The Boston Globe, and after similar accounts emerged across the country, the United States Conference of Catholic Bishops asked Ms. Blaine and Mr. Clohessy to address them at a pivotal meeting in Dallas. American bishops eventually adopted a zero-tolerance policy and pledged to remove priests credibly accused of abuse.

But since then SNAP has often accused bishops of failing to keep these promises, and the group continues to be seen by the church as an adversarial force.

Archbishop Wilton Gregory of Atlanta, who was president of the United States Conference of Catholic Bishops at the height of the scandal in 2002, recalled on Monday that he had first met Ms. Blaine when he was an auxiliary bishop in Chicago. He had helped her obtain a closed church to use as a Catholic Worker house.

“She was a woman of faith; may God be merciful to her,” Archbishop Gregory said.

Besides her husband, Ms. Blaine is survived by her stepsons, Brett and Joshua Rubin; two step-grandsons; three brothers; and four sisters, one of them her twin.