A few weeks after the devastating extent of child sexual abuse by Roman Catholic priests in Pennsylvania was laid bare in a 900-page grand jury report, Father Michael Stumpf was approached by one of his parishioners.

“She demanded: ‘What do you know?’ And with a shock, I realised that because I’m a member of the clergy, people think I’m complicit. And I can totally understand why,” said the priest at St Mary of the Mount, which overlooks downtown Pittsburgh.

“I’ve had feedback in the last few weeks that I’ve never experienced before. It’s been challenging and disturbing – but also encouraging. The candour with which people have spoken has been refreshing. There’s an awakening and an empowerment because of this.

“Are we seeing fewer people coming to church, a decrease in people’s giving? Yes, some – a little. People let their voices be heard in one way or another.”

One of his parishioners, who did not want her name published, was more blunt: “Close friends of mine feel the church is tainted. Some won’t attend mass any more.”

On Thursday, the US justice department opened a landmark investigation into child sexual abuse inside the Roman Catholic church in Pennsylvania.

But the reverberations of the grand jury report, which detailed how hundreds of priests had raped, beaten and abused vulnerable children, and how “the men of God who were responsible for them not only did nothing; they hid it all”, have also been felt way beyond Pennsylvania.

Across America, the Catholic church is reeling from the fallout. At least 13 states have launched official investigations; Cardinal Donald Wuerl, the archbishop of Washington, resigned; pressure is mounting for those accused of abuse to face justice, along with those who covered it up; pews are emptying. In Rome, Pope Francis is feeling the blowback as his popularity ratings plummet and his enemies circle.

Some see it as the church finally facing its own day of reckoning.

“This is a seminal moment,” said John Allen, the editor of Crux and a veteran observer of the Vatican. “Pope Francis clearly has questions to answer, and the clock is ticking.”

According to Andrew Chesnut, a professor of religious studies at Virginia Commonwealth University, “the scale of the crisis is now threatening to eclipse Pope Francis’ progressive agenda. It has unleashed an internecine battle.”

Pope Francis is feeling the blowback of multiple sexual abuse scandals as his popularity ratings plummet. Photograph: Pacific Press/Barcroft Images

This month, the Pew Research Center found a sharp fall in confidence among US Catholics in Pope Francis’s handling of the abuse scandals that have engulfed the church this year. Only three in 10 said he was doing a good or excellent job on the issue. And the proportion of those who had a generally favourable view of the pope had dropped by 12 points, down to about seven in 10.

A CNN poll taken in September found that the proportion of US Catholics who had a positive view of Francis was 63%, a slide from 83% in 2017.

Stumpf – who celebrated weekday morning mass at St Mary’s with just seven people on the day the Guardian visited – said: “This is a pivotal moment in the church’s history. People won’t accept it not changing.”

Jim VanSickle certainly won’t. He kept the abuse he suffered secret for 37 years, telling only the barest details to his wife and parents. But earlier this year, he discovered that the same priest who abused him all those years ago was now being publicly accused by another survivor.

“It sent me into a tailspin, I was beside myself,” he said at his home in the Pittsburgh suburbs. “I couldn’t think of anything else, except I knew I was going to have to step forward to support this kid. And if I was going to break my 37-year secret, I wasn’t going to do it small.”

Soon after, VanSickle gave evidence before the grand jury, alleging that the Rev David Poulson had carefully groomed him over a period of years, luring him into an intense emotional dependence and a growing intimacy, before attempting to rape him in a seedy hotel room. The experience left VanSickle traumatised and with borderline personality disorder.

“I isolated myself, sealed myself off from relationships. I hurt my wife, my children and myself,” he said. “But now each time I tell my story I heal a little bit more and I become stronger. I’ve found a huge community of survivors. So many of us think we’re the only ones with this secret, but now we cry together and support one another.”

VanSickle has become an informal spokesman for survivors in the state, learning fast about the law, political processes, public speaking and media appearances. “I hope I have helped others to have a voice. That has become my ministry,” he said. Although he is no longer a practising Catholic, he has a powerful Christian faith.

But justice is beyond his grasp. Pennsylvania state law allows victims of child sexual abuse to pursue criminal cases against perpetrators only up to the age of 50. VanSickle is 55; the average age of survivors reporting abuse in the state is 52.

VanSickle is now campaigning for a two-year window to be opened allowing survivors over the age of 50 to seek justice.

Other Pennsylvania survivors are bringing civil cases. Last month, a class action lawsuit was filed against eight dioceses in the state demanding the names of all priests accused of abuse in the past 70 years be made public. At least 20 names were redacted from the grand jury report – and there are believed to be other unidentified abusers.

“We’re done being lied to,” said lead plaintiff Ryan O’Connor, 46, a victim of child sexual abuse and the father of two children who attend a Catholic school, when the case was launched. He wants to be certain that his own children are not in danger. “I’m speaking out for all survivors and all parents who want to know why this church believes they are above the law.”

Juliann Bortz, 68, is suing the church for defamation. She claimed it launched a smear campaign against her after she reported being sexually abused by a priest when she was a teenager, hiring investigators to dig up “irrelevant, unrelated [or] false ‘dirt’” to discredit her. The church has denied her claim.

Meanwhile, a telephone hotline opened by the office of the Pennsylvania attorney general after the release of the grand jury report on 14 August had received more than 1,200 calls by early October.

The report had been a “tipping point”, said Benjamin Sweet, a Pittsburgh attorney representing a number of survivors.

VanSickle described it as a victory in a war against the Catholic church that was only just beginning. “I used to think it was just a few bad apples. Now we’re finding it’s a bad orchard, with a few good apples,” he said.

“I have Catholics reaching out to me, saying: ‘How do I know my parish priest is not an abuser, or has covered up abuse?’ I tell them: ‘You don’t.’ People are angry. This is not going to be the same church when we are done.”

That rage has reached the heart of the Vatican as wave after wave of scandals – in Chile, Germany, the Netherlands and Australia as well as the US – have broken this year. Pope Francis’s conservative enemies have seized the opportunity to attack him, and even call for his head.

A toxic web of accusations and counter-accusations has centred on Theodore McCarrick, the former archbishop of Washington. Francis accepted his resignation as a cardinal in July after McCarrick was accused of sexual abuse of a minor. Allegations and rumours about McCarrick had swirled for years, but had not prevented his elevation to archbishop, cardinal and papal envoy.

McCarrick has not commented on the allegations.

The Rev Michael Stumpf has found it ‘deeply painful’ to be confronted by angry and suspicious parishioners. But it was also appropriate, he said. Photograph: Justin Merriman/The Guardian

In early October, Francis ordered a “thorough study” of Vatican archives on McCarrick – an investigation that the Vatican acknowledged may conclude mistakes were made. The pope has also summoned senior bishops from across the world to Rome in February to discuss the sexual abuse scandal.

But, according to Allen, those steps are not enough. “Assurances and mea culpas are not going to do the trick. People want to see results,” he said.

“First, they want to see a meaningful system of accountability for bishops who cover up abuse. The church now has a system for punishing priests who commit abuse, but what about the bishops who cover it up?

“Secondly, right now, they want the truth about the McCarrick situation – how a guy who had rumours of sexual misconduct surrounding him could have become an archbishop, then a cardinal, then a key papal adviser without those concerns ever raising red flags.”

Chesnut said Francis had been “inept at getting in front of this crisis, and there is no doubt people are voting with their feet. There’s no doubt we’ll see an acceleration of people saying they no longer want to be part of the institution of the church.”

At St Mary’s on the Mount in Pittsburgh, Stumpf has found it “deeply painful” to be confronted by angry and suspicious parishioners. But it was also appropriate, he said.

A culture of deference and a belief in the moral superiority of the clergy was crumbling. “Parishioners have had an idealistic and unrealistic expectation of us. That’s changing now, and it’s glorious.”

Would the church recover from this crisis? “I don’t think ‘recovery’ is an appropriate word,” he said. “I hope and pray it will be transformed.”