Philadelphia (CNN) – It's been four weeks since the beginning of the trial of the highest ranking U.S. Catholic Church leader charged with covering up the crimes of priests against children.

The main issue is not whether sex abuse occurred, as defense attorneys have pointed out, but how the Archdiocese of Philadelphia - Monsignor William Lynn in particular - handled the allegations against priests in the diocese.

The trial against Lynn and the alleged offending priest, the Rev. James Brennan, has already created a shake-up in Philadelphia's Catholic leadership, according to Catholic commentator and blogger Rocco Palmo.

"It's a shift you see once in 200 years," Palmo told CNN.

And, he adds, the trial could have a worldwide ripple effect on the entire Catholic Church, which has been rocked to its core by widespread allegations of sex abuse by priests.

On March 26, jurors first began hearing graphic testimony from former Catholic schoolchildren, parishioners and police detectives alleging the lurid lifestyles of predator priests.

Lynn, 61, who served as the secretary for clergy under former Philadelphia Archbishop Cardinal Anthony Bevilacqua, is charged with child endangerment for his role in handling abuse complaints, including allegations against his co-defendant, Brennan, 48, who is charged with attempting to rape a 14-year-old boy in 1996.

Both men have pleaded not guilty.

Testimony has been heated as teary witnesses take the stand describing the alleged abuse by dozens of diocesan priests during overnight stays, at vacation homes or at parish rectories.

The trial has provided a rare behind-the-scenes portrait of one of the largest Catholic archdioceses in the United States. In addition to the graphic testimony, hundreds of pages of internal personnel files of priests accused of child sexual abuse - some of them confidential - are now part of the court record.

And that could have a deeper impact on Philadelphia's Catholic community, according to David Clohessy, director of the Survivors Network of those Abused by Priests (SNAP).

"These revelations and disclosures have to help parishioners face the painful reality that, just like victims, they, too, have been horribly betrayed and misled," Clohessy said,

"When you see handwritten memos from very smart, high-level church officials, this unambiguous deception and selfishness really cuts through denial."